My previous ex had a relationship with a girl, the last 2 years of our relationship. So I’ve always been “on guard” with all relationships after that one.
I found a guy who experienced a similar issue with his ex wife (outside relationships discovered via text msg,) so I felt good going in. I recently discovered that he’s been messaging girls/couples on Craigslist when I’m not staying over at his place. I can go into why I know this, but just know it wasn’t due to over snooping on his devices.
I don’t know how to bring it up to him. I want to because since I figured it out, I’ve made every excuse I can think of for us not to have sex for fear of transmittal. What is hard too, is I love him. He’s an amazing partner, if I didn’t know this was happening behind the scenes. Help please? Is there a way back from this?
LemonVibe 
i would advise you to confront him about it. Things like this just grow in the dark. It will be a challenging conversation but its one that needs to happen if your going to grow in your relationship. Real true love is tested by how you overcome and deal with conflict. You don’t need to think the worse. Just because he looking on Craigslist doesn’t mean he’s sleeping around, those things aren’t synonymous with each other. So calm down. Im sure this is upsetting but you cannot be overruled by your emotions. Whats more likely is that he’s just looking. Why he’s looking is the bigger question. Could it be because things are stale and the same and he’s just wanting to explore. If you intend on working on the relationship. You should probably consider counseling. Talking through is in a sensible calm manner sometimes can only happen in a third party setting to keep things civil. but understanding fully your partner in this situation will help you both learn about one another. @blksports980
He is not a amazing partner. A amazing partner doesn’t cheat on you. An amazing partner doesn’t make you worry. Move on and aim higher. You deserve better.