You've been hanging out with this guy for a while and everything is great. That's what you tell people. The truth is, everything is not so great. Things he says and does don't add up. When you're together, there is often something forced, even fake, about how he relates to you. Maybe you're beginning to find out things about his sex life that he has tried to hide. Maybe he has some odd sexual proclivities. What used to be charming or thrilling is starting to freak you out.
The guy may be going through a tough time. He may be a sexual dynamo. He may be banging someone else. Shit happens. But there may be a different answer.