Sex is a crucial part of many romantic relationships, but sometimes life gets in the way.
Things like stress, work, chores and hormonal changes can all have a negative impact on our sex lives.
The feeling that you "have to" have sex in order to sustain your relationship is called maintenance sex. It happens when one or both partners aren't in the mood but have sex out of obligation – often because they know the importance of intimacy.
Experts say it is not necessarily a bad thing but can become problematic in a relationship if there are underlying issues that are being swept under the rug.
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"It's totally OK to not want to always have sex like you used to," says Celeste Holbrook, a sex educator based in Fort Worth, Texas. "As we grow older, we realize sex doesn't come easily. It's always work and always a negotiation. So it's natural to have to put in more mental work to fuel your relationship's initial novelty."
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Maintenance sex has plenty of benefits
Research has shown that couples who have sex at least once a week are happier than couples who don't. Sex also releases endorphins to create a feeling of closeness between partners – something that isn't replicable in platonic friendships.
"Sure, you can have intimate conversations with your partner, but you can also do that with your friends," Holbrook says. "There's nothing more vulnerable than being naked with someone, and having sex is this one thing that differentiates marriages from relationships with friends."
Maintenance sex can help reinvigorate that missing spark, according to Allison Moon, author of "Getting It: A Guide to Hot Healthy Hookups and Shame-free Sex."
"It encourages people to try new things, open up dialogues about desires and how their bodies and libidos are shifting," says Moon. "It's an opportunity for people to engage in fun, affirming sexual touch even if it doesn't come from the deep rutting urge it came from when the relationship was new."
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When maintenance sex can become problematic
Experts agree engaging in sex to keep your partner happy is a perfectly valid choice. But if one partner feels that sex is always an imposition, that's when it becomes a problem.
"Maintenance sex only really works when it's done with true consent and a certain amount of enthusiasm to make one's partner happy," Moon says. "If the only sex you're having is maintenance sex, something else may be going on in the relationship that needs to be addressed."
The experts also emphasized that maintenance sex is never about pressuring or guilting a partner into intercourse, and no one should ever feel coerced into doing something they don't want to do.
"It's important to communicate with your partner and explore what is leading to the low sexual desire or disinterest in sex," says Rachel Needle, a licensed psychologist and the co-director of Modern Sex Therapy Institutes, who recommends digging into the issue "on your own or with a mental health professional who specializes in sex."
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Holbrook believes people often misunderstand the idea of maintenance sex, and she prefers the term "intentional sexuality," which reframes sex as "a negotiation between partners."
"Maintenance sex has this underlying tone of 'just do it,' which is highly problematic," Holbrook says. Instead of saying "4 o'clock on Thursday is the time to do it," intentional sex "places some intention on when and how you have sex in a way that feels good for both partners."
But at the end of the day, good healthy sex isn't dictated by how planned or how frequent it is.
"There are plenty of people in blissful, sexless marriages. And there are plenty of people who (have sex) like bunnies," Moon says. "The best amount of sex is the amount you want to have."
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Contributing: Joshua Bote