It's easy enough to say that if you're not sure if you're having good sex, you're not having it—but I'm not convinced that's necessarily true. I have this theory that sex is a lot like your elementary school chemistry class (stay with me). You have to put the right ingredients together in order to make that volcano explode, but as time goes on and you keep dumping in the baking soda, that explosion gets less and less fantastical. College Candy: 10 More Things You Should Know About Sex
The thing with sex is that you can't always tell when it's just a rut or when you're sexually incompatible. I mean, at first glance they both look similar—lack of sex, frustration, etc.—but there are a few differences. So before you make any rash decisions, ask yourself: is the sex just getting boring (but fixable!) or are you and your partner sexually incompatible?
You might be incompatible if…
It's never been great.
Pain and a lack of chemistry are a couple of good indicators that it's more than just boring. It's nearly impossible to enjoy sex if it's painful (unless you're into that), and sometimes an off-kilter penis-to-vagina ratio can cause more than a little discomfort. If you never went through a "honeymoon period" where the sex was incredible but eventually died off—or if that period was disappointingly short (I'm talking a week), then perhaps incompatibility is the issue, not a lack of excitement.
You're fighting about frequency.
It's normal for one partner to have a higher or lower sex drive than the other, but if that difference is so great that it's causing nightly arguments, it's probably not something that can easily be fixed. The problem with hugely different sex drives is that it leaves one partner feeling constantly rejected and the other constantly annoyed. There are other ways to solve this—offer a "loving assist" during masturbation, for instance—but if the biggest issue in your relationship is the infrequency of your sexy time, it might be a sign that you're just not sexually compatible. College Candy: 10 Reasons You Should Break It Off
On the contrary, you might just be in a rut if…
It used to be great, but now it's becoming a little lackluster.
I have some good news—this is completely normal. Remember that chemistry analogy I used before? It's the same thing. After doing the same thing consistently (even if it's super fun) it can still get a little boring and predictable. Even more good news is that this problem is completely fixable; all you need is a little excitement. Get out there and have sex in places you haven't, try new positions, or introduce some toys. Sometimes a change of scenery is nice—but a change of sexy routine is even nicer.