Every once in a while, just when everything in your relationship seems fine, you witness what feels like all your friends (IRL or on Facebook) suddenly breaking up.

While it's true that breakups can be holiday-related or seasonal, having a group of freshly-single BFFs talking about what went wrong in their relationships can make your supposedly stable partnership feel unexpectedly shaky. You begin to wonder: are you next?

Turns out, when it comes to divorce, you are 75 percent more likely to split with a spouse if you see a close friend or family member do so (and 33 percent more likely if it's a friend of a friend). While breakups may not be literally viral, there's something about seeing so many seemingly-great relationships dissolve at once that feels like an uncontrollable outbreak. I spoke with Dr. Bella DePaulo, Academic Affiliate, Psychological & Brain Sciences at the University of California, Santa Barbara, about why seeing your friends' relationships dissolve makes you analyze your own:

1. You question the relationship sacrifices you’ve made

Anyone who's in a relationship will tell you that it takes work and involves compromise, but that it's worth it for the right person. But seeing your friend who moved to a new country only to get dumped by the guy she did it all for can make you immediately worry if you've given up anything huge for your relationship.

"Important life pursuits, such as meaningful work or travel or big moves to pursue big dreams can get demoted as priorities, in favor of the romantic relationship," says DePaulo. "When we see our friends’ romantic relationships crumble, suddenly the script seems iffy." While you don't necessarily need to break up if you feel like you haven't dedicated enough time to your career, it's good to channel this panicked feeling into something useful: like figuring out which areas of your life feel hollow.

2. You realize you gave up some great friendships for your now not-so-great relationship.

You've totally known that person who acted like your friendship was just a placeholder until they got into a relationship — and then you never saw them again except for the rare times their boo was out of town. Being in a relationship, even when you still prioritize your friends, makes it hard to pencil everyone in, and married couples statistically lose some of their social bonds in favor of their relationship.

"Our most important friendships often last longer than many romantic relationships or marriages," says DePaulo. "If you follow the usual script and ignore your single friends once you get involved in a serious romantic relationship, you may just find that they are not so interested in being there for you after your relationship ends." If you get nervous seeing your newly-single friend feel very alone because she abandoned all her friends in her last relationship, it just means you should make sure to keep your own personal network tight. Because breakup or not, having a balance of a great relationship AND great friends is so much better than investing everything into one boyfriend (it's also much healthier).

3. You might just really miss the freedom of being single.

Having all your now-single friends hang out without you because you have date night planned can make your relationship suddenly feel a little oppressive. "When you see your single friends embracing their friends and their newly single lives, you are being reminded of what’s so great about friendship and about getting to choose who you want to see and when you want to see them, without worrying about what your partner might think or want," says Dr. DePaulo.

Whether it's your BFF having more friend time in her schedule, or more flexibility to pursue the hobbies she put on hold, singlehood can seem amazing if you're in a relationship where you don't feel free to do those things normally. Basically: if you're going to date, get you a partner who doesn't expect to have dinner every Friday night or get mad when you do stuff on your own.

4. It makes you wonder about hooking up with other people.

Witnessing your friend leave a relationship and then excitedly talk about all the hot hookups she's having can make a sexual decline in your own relationship feel like the kiss of death. While it's normal for a long-term couple's sex life to experience ups and downs, if the idea of not having sex with them anymore immediately sounds appealing, that's a big sign.

"It could [also] jolt you into reassessing in a bolder way, by considering whether it might be nice to just take a break for a while," says Dr. DePaulo. "From sex and from romantic relationships." If either hooking up with new people or not having sex at all becomes a preoccupying fantasy, you have your answer.

5. You wonder if you’re in a relationship only because you're expected to.

Just like breakups can feel contagious, so can relationships – when all your BFFs suddenly shack up with new partners, it's easy to feel the pressure to do just the same. If the same friends who entered relationships when you did are all broken up now, it can make you think about how much societal pressure played a role in your own coupling up.

But questioning the real reason you're in a relationship, as scary as it feels, is never a bad thing. "When we start thinking about romantic relationships in more enlightened ways, maybe we will be less likely to jump into a dubious romantic relationship just because many of our friends are currently coupled," says Dr. DePaulo.

Your friends breaking up doesn't mean that you have to, or that all monogamous relationships are a sham. But when so many people divorce after seeing their friends do it, you start to wonder if they're choosing what they've wanted for a while because it feels acceptable and okay to them now. All to say: go forth and date. Just keep your friends – single or not – close, and do what you want to do, not what everyone else is.