I have never posted but I wanted to reply because I have experienced something similiar. My husband passed away in December 2016 very unexpectedly. I found he was texting, and DMing with two women very sexual things. I also had no idea this was going on and was completely blindsided.
What has helped me most is talking to a grief counselor, specifically one who specializes in complicated grief. I also have shielded his and my family because I don't want to ruin their memory of him and I don't want them to have to figure out how to forgive him. It has helped tremendously to have an unbiased person to talk about everything with and be able to get it out.
When I'm angry I have a few things I remind myself and I don't know if those will help you too.
1. Even if he were here there is nothing he could do to take the hurt away.
2. I fulfilled my vows to him and did everything right by him.
3. Above all else this was not my fault. I did nothing to cause this, it was his own demons he was fighting and he is now released from them.
I'm sorry you are dealing with this. It is a tough complicated situation to be in.
