For engaged couples with a wedding on the horizon, it’s important to take stock of your relationship before, not after, you walk down the aisle.

Instead of spending all of your time and energy planning the wedding, think about investing some of those precious resources in your relationship ―  particularly if you have doubts about whether you want to get into a lifelong partnership with the person you’re engaged to.

Below, marriage therapists reveal the behaviors that are serious enough to warrant postponing the wedding until you and your partner work things out. And if things still don’t improve, perhaps it’s worth reevaluating the relationship as a whole.

They frequently put other people and plans before you. 

Does your partner cancel plans with you when something better comes up with his buddies? Or maybe she picks up a non-urgent work call while you two are out to dinner celebrating your birthday. If so, it might be a sign that your partner isn’t prioritizing you and your relationship.

“People get married for lots of reasons,” marriage and family therapist Aaron Anderson told HuffPost. “It’s not always for love. Make sure you’re not marrying someone who’s marrying you out of convenience. Make sure they’re putting you first. You don’t want to be the understanding spouse for the rest of your life, or soon you’ll start feeling like a doormat.”

They don’t communicate well.  

Instead of having a productive conversation about a tricky topic ― like sex, family issues or money ― your partner either argues with you about it or just avoids the discussion altogether. It’s been said time and time again, but communication really is the cornerstone of a strong marriage. If you can’t talk candidly about the tough stuff, you might not be ready for marriage quite yet.

“The problems that develop when long-standing problems remain unsolved can ruin your relationship,” Tina Tessina, psychotherapist and co-author of How to Be a Couple and Still Be Free, told HuffPost. “Make it a point to talk about whatever seems difficult: You need to know how well you two can discuss the difficult things that will arise during a lifetime together.”

And if you can’t find a way to discuss these things without it turning into a blowout fight, it may be wise to see a couples therapist who can help you sharpen your communication skills.

“If that doesn’t work, the relationship probably won’t work either,” Tessina said.

They’ve cheated on you. 

Infidelity doesn’t necessarily have to be a dealbreaker, but it’s certainly something that might give you pause leading up to the wedding. If your partner is genuinely remorseful and willing to do the work to uncover what drove them to be unfaithful in the first place, that’s a good sign. Before tying the knot, it’s also worth taking a closer look at any underlying issues in the relationship that could have contributed to the infidelity.

“While I disagree with the saying, ‘Once a cheater, always a cheater,’ there are always some significant mindset and behavior changes necessary to prevent this behavior from repeating,“ Kurt Smith, a therapist who specializes in counseling men, told HuffPost. “These new changes should be proven before getting married.”

They’ve stopped having ― or talking about ― sex with you.

Over the course of a relationship, it’s normal for both partners’ levels of sexual desire to fluctuate. What matters is whether you and your partner are able to have a healthy discussion about these inevitable ups and downs and can express what you do (and do not) like in bed. If your partner stonewalls you or refuses to take your concerns seriously now, it’s unlikely these issues will magically resolve themselves after you say “I do.”

“If you’re feeling strain in your sexual relationship now, then imagine what several more years is going to feel like,” Anderson told HuffPost. “A lifetime is a long time to be having bad sex. People think sexual difficulties are a pretty shallow reason to call off the engagement, but they’re even less understanding when it’s the cause of an affair or a divorce. Make the decision now or get the problem fixed before tying the knot.”

They’re dealing with addiction issues: drugs, alcohol or gambling.

Again, this one doesn’t have to be a dealbreaker if your partner is truly committed to their recovery. But untreated addictions can put a significant strain on the relationship, so you should not just turn the other cheek ― no matter how much you may love this person. If they are ready and willing to get help, that’s one thing. But if they’re still in denial, that’s another.

“Addictions aren’t easily or quickly resolved,” Smith told HuffPost. “It would be a big mistake for a partner to think they’ll be able to change this problem behavior about their future spouse. I can’t tell you how many spouses I’ve counseled who overlooked this in the beginning because they thought it wouldn’t be that bad.”

They’ve recently gone through a major life event like a career change, big move, or the illness or death of a parent.

These are not reasons to call off the wedding altogether, but they may be enough for you to at least consider the timing of your nuptials. It might be worth postponing the wedding until things settle and some level of normalcy returns to your partner’s life.

“Trying to build a foundation on shaky ground is never a good idea,” Susan Pease Gadoua, marriage therapist and the co-author ofThe New I Do: Reshaping Marriage for Skeptics, Realists and Rebels, told HuffPost. ”One couple I worked with was struggling from the fallout of the husband’s father’s illness, which took the newly married husband away from his wife. Although she understood on the one hand, on the other, she was resentful of how much he had to take care of his father. From her perspective, this should have been their newlywed time together.”

“In turn, he became resentful toward his new bride because she didn’t understand his relationship with his dad,” Gadoua continued. “Looking back, the wife could see that her husband was not fully present on their wedding day and those months prior. Intuitively, she knew he was not in a position to get married, but she thought they could ride the storm together.”

They’re controlling and emotionally volatile. 

We all have good days and bad days. On bad days, we may not be the best versions of ourselves ― perhaps we’re cranky or short-tempered. But is bad behavior the exception or the rule with your partner? If, more often than not, your partner is having emotional outbursts, trying to control you (which could be a sign of emotional abuse) or exhibiting narcissistic behaviors, these are major warning signs that shouldn’t be ignored, Smith told HuffPost.

“Any behavior of this kind should be discussed with a mental health professional to determine the significance,” Smith said. “If characteristics such as these or others make you question if they might be a problem, they must not be ignored. These are some of the big causes for partners seeking marriage counseling later on.”

They’re dealing with significant mental health issues. 

In a given year, nearly 1 in 5 American adults will experience a mental health condition. It’s that common. But if your partner is dealing with a severe, debilitating issue, the stress of an upcoming wedding may only add to their already very heavy mental and emotional load.

“I had clients who came in for premarital therapy a month before the wedding date and with each session, the male client slipped deeper and deeper into a dark hole of depression,” Laura Heck, couples therapist and creator of the online couples therapy series “ForBetter,” told HuffPost. “He hired an individual therapist who specializes in depression, who recommended he check himself into the hospital for a few days to keep him safe from self-harm. This was a major red flag and the point where it should have been clear that the wedding date was no longer the top priority.”

Against Heck’s advice to postpone the wedding, the couple married days after the groom was released from the hospital.

“Weddings can be stressful events; in fact a wedding scores a 50 out of 100 on the life change unit scale,” she said. “Anyone can experience an increase in anxiety or any preexisting conditions; however, suicidal thoughts and self-harm behaviors should take precedence and give pause to the decision to move forward with a looming wedding date. My recommendation is to postpone it and get to the bottom of where these symptoms are coming from.”

They keep secrets from you. 

Say your partner went over budget one month or had dinner with an ex: Do they tell you, or say nothing and hope you don’t find out? Admitting our wrongdoings isn’t easy; it requires honesty and vulnerability. But ultimately, being upfront about these mistakes can help build a strong foundation for your future together.

“Lying to your partner about whether you have broken an agreement does more damage than breaking the agreement,” Tessina told HuffPost. “If you slip up, tell the truth. If it’s your partner who has slipped, be open to listening to him or her without blaming or getting upset, so the two of you can negotiate a solution to the problem.”

In any successful relationship, trust must be mutual, Tessina added.

“By that definition, if there’s a secret you don’t want to share, something may be wrong with the trust between you,” she said. “Sharing damaging secrets is an excellent way to test the viability of the relationship. I advocate sharing all.”