Sorry my first answer was flippant - I wasnt sure if it was one of the usual flippant questions.
I think you should make it clear what you are looking for when you meet guys and if they are interested enough in you as a person, then they'll be back, and not just look for a quick one-nighter.
There are so many guys on dating sites who are married, as raggy said, and they are not usually the best places to go looking.
After one of my relationships ended nearly 2 years ago, I decided not to bother with dating or seeing anyone again, and then totally out of the blue, I met this woman at a friend's house, and things just clicked.
Nine months later, it's still clicking.
Sometimes when you look, nothing appears, or the things that do appear are not what you hoped for.
Just take your time to get to know guys, and if they don't bother getting to know you, and disappear just because sex isn't on the cards, then they're probably not worth getting to know
Goos luck