Sex isn't everything in a marriage, but for most people, a healthy, regular sex life matters quite a bit.
Sex therapists can vouch for that. Below, they share seven issues that can ruin a relationship if left unaddressed.
1. The couple no longer has sex.
"Partners end up alienating each other on a very deep, very primal and sometimes emotional level," she told The Huffington Post. "Very frequently the couple not only avoids sex, but the discussion of the problem itself. That only leads to a further sense of isolation and loneliness for the partners."
When couples in sexless marriages come to Cooper's office, she helps them broach the discussion without placing the blame on one person in particular.
"The sexually frustrated partner needs to 'break the ice' and let their S.O. know how much they miss them," she said. "That's a much better approach than arguing or blaming the other."
2. One partner doesn't feel sexually desired.
Feeling wanted and desired is a huge turn-on, especially for women. As sex researcher Marta Meana once put it in an interview with the New York Times, for women, "being desired is the orgasm." When a partner fails to reassure a woman of her desirability, their sex life naturally takes a hit, said Laura Watson, a sex therapist and the co-host of the sex advice podcast Foreplay.
"Resolving the issue is all about exploring expectations. You have to consider how intimate couple time can lead to better and more sex," she said. "It also doesn't hurt to make sure your partner is getting good sex with plenty of orgasms so she'll want to do it."
3. There's a breakdown in intimacy after an affair.
Broken trust after an affair can be a hard thing to mend and your sex life will take even longer to restore, Cooper said.
"It takes a lot of effort and work by the unfaithful partner to re-establish trust. Meanwhile, the betrayed partner needs to better understand what led to the affair," she said. "Often, the couple needs to create a new sexual contract of sorts, that addresses the needs that were not being met or hidden.
If the unfaithful partner continues to have contact with the other man or woman in secret, it may be impossible to repair the emotional and erotic bond, Cooper said.
4. There's no physical attraction.
In long-term couples, waning sexual attraction can do a number on the relationship, said Moushumi Ghose, a sex therapist and author of Classic Sex Positions Reinvented.
"Sometimes, it's a matter of one spouse letting themselves go," she said. "Obviously, life happens and the daily stressors of work, marriage, and having a family can take its toll, but people who are no longer physically attracted to their partner sometimes take it as a sign that their partner has given up on themselves and their relationship."
5. Physical barriers to sex become a scapegoat.
These problems should be addressed with a doctor, but there's usually some emotional work that needs to be done by the couple as well, said Celeste Hirschman, a sex therapist and the co-author of Making Love Real: The Intelligent Couple's Guide to Lasting Intimacy and Passion.
"When these functional problems end up being blamed for all the sexual problems ― and sometimes, problems in the relationship in general ― it blocks the couples ability to discuss their sexual and emotional needs," she said. "Couples need to see beyond the dysfunction and look at the dynamic that's been created around it, like fear of being undesirable or blaming the other person for everything."
6. Sexual interests and fetishes are laughed off.
We all want different things: When your partner opens up about how they want rough sex or to role play, the worse thing you can do is disregard it or laugh it off, said Ava Cadell, a sex therapist and author of NeuroLoveology: The Power to Mindful Love & Sex.
"I tell my clients that everything is negotiable, even in the bedroom," she said. "If one partner enjoys BDSM and the other is not that into it but wants something else, I recommend they each share three romantic fantasies and make one a reality for the other."
From there, continue to share your sexual fantasies and boundaries without any fear of judgement or rejection, Cadell said.
7. There's a desire discrepancy.
Many couples suffer from a "desire discrepancy," a situation where one partner wants sex more than the other. This poses a big problem for most couples because the lower-desire spouse holds all the control of the couple's sex life, whether they realize it or not. Eventually, the higher-desire spouse grows resentful, said Megan Fleming, a psychologist and sex therapist in New York City.
"Sex mismatches are at risk for affairs and divorce if not addressed, since the more sexual partner often can't imagine living the rest of their lives this way," she told HuffPost. "After all, they committed to a marriage, not a life of abstinence."
Don't wait until your partner is at their wits' end before addressing the issue.
"The good news is that reasons for low desire are complex but treatable," Fleming said.