There’s definitely ways to rebuild trust but you’ll have to want to. It takes effort from both parties in order to move forward. You can look up moving forward after cheating and there are some great articles that go in length on how to do so. I recommend therapy as well, because broken trust can lead to more issues.
Honestly it would break my heart, it would break anyone’s. You’ve put a mad amount of trust forward and to have it betrayed like that is awful and I’m so sorry. Personally I’d question on why when his ex added him, he didn’t immediately just block, or if he added her back, why wouldn’t he say he’s got a beautiful wife and kids and he is happy with his life? That he doesn’t want to think of the what if’s because he has every thing he wants? Those are the questions I would put forward to him “why did you respond?” “Is there something you’re missing here?” Because no one just goes with stuff for no reason especially with an ex. He needs to lay it out for you what he wants, he needs to meet your expectations of him in future as well for it to work for example that ex and any other ex’s stay blocked. Doing that doesn’t change the whole thing though and it doesn’t change who someone truly is. It’s good he came forward about it, not many men do or would. But there’s something else going on
With him personally if he felt that way to respond to that and keep her added. Furthermore do you think he will or can change? If yes then I would advise couples therapy. If no then it’s not going to be able to move forward because you know what you know and if you stay in a relationship where you can’t build trust then you’ll end up resenting him and hating him and it’ll ultimately harm yourself more. If it was me I’d have left my partner personally. But everyone is different and your relationship is also different so I would think about what you want going forward, what you will need to move past it
Idk but I’d leave
Hey Sis, Basically it sounds like your husband betrayed your trust if nothing else. And moving on from that is totally in your court. If this something you can overcome. And if so are your wanting to go to counseling for it ? Trust is something that takes so long to build yet only a few moments to be broken. I am sorry you are going through this.