If you’re 100 percent sure that he cheated on you, then why would you want to go back with him?
If you need some closure, to say goodbye, or if you need to confront him because you’re 90 percent sure he cheated, but want to hear it from him so that you can be 100 percent sure one way or the other, then you should contact him and ask him if that’s what happened.
It definitely sounds like there’s been some change in his behavior, and it’s impossible to have a working crystal ball or to be able to read his mind, so either trust that he cheated on you and move on — no break necessary — or have a face to face and ask him what happened and if what you’d heard is true.
Regardless, if after 6 months of dating your boyfriend tells you he needs “a break”, then I wouldn’t advise you to waste another minute of your precious time with him! There are men out there who wouldn’t give you up for all the world for “a break.” If he can’t appreciate you, then you’re much better off with someone else, who will! 🙂