Usually communication is the key. Listening to what each other wants and needs but not compromising ones beliefs or self respect. For example if your guy wants to have a threesome and you don’t, you should never feel pressured into doing something you don’t want to do.

If once in a sexual relationship you feel you aren’t compatible in the bedroom you should look elsewhere for a partner more understanding and in tune with your needs and desires.

Lets not forget that some people are just cheaters and will cheat regardless of the situation with their partner