My wife and I have been together for 10 years (married for 4), and we're each others only partners during that time. We fuck a lot. Married couples are usually much happier in their sex lives than single people. There's new sex, and there's good sex. if you need new sex, don't get married. if you want good sex, get married. but don't just marry a hot bitch. as i have said before on this site, actually make sure you can have fun with a person one on one, and not just when having sex. my wife and i are best friends, and we have sex. its great. but i have to reiterate the fact that she's not crazy, she's rational, and smart. one of her friends complained to her that her husband/boyfriend was getting too "weird" in bed. her response was,"well, you're the one person that they get to be crazy sexual with, and they want to do that with you. deny that guy for too long and he'll either start fucking someone else, or he'll remove himself emotionally from the relationship." her friend did not care for my wife's response...they divorced 2 years later.
wife test: take a car trip with them. if they only talk when conversation naturally presents itself, that's a keeper. nothing screams crazy and insecure like a woman who always talks. women like that should be eradicated.