DB after cheating...

Long story short, i catched my wife in a secret conversation with a guy, after they met once last summer for a few hours. And after that everything changes The sex becomes more less And never more just a 15 minutes. Somethimes just a quickies before bed... Nothing happened like that before. We had it 2-3 times a day before and now its just 2 times a week (if im lucky). I started to ask about it, but she regrets most of the time...in my head is like - i have to do the "job" so she wont cheat again...but how, when she denies? My brain is messed up I hate porn, but my HL makes me to watch and masturbate each morning before work so i can clean my head and to feel just a little bit more satisfied. I wont cheat, but i really dont like this type of relationship.