Not an affair but feels like a similar betrayal.
Background:
2 years ago I had a big falling out with DP's DB. DB was so overwhelmingly in the wrong that even his DP and DM sided with me. I gave DP a him or me ultimatum and he chose me.
His name has never been mentioned again (in my presence at least) by DP or DMIL (who I get on with v well). tbh I never expected DP to never see DB again but the subject never came up. A few months later I did find some stuff of ours that was at DB's and that he had obviously got back from him but nothing was ever said. DMIL said recently that she hadn't seen DB's DCs since 'the incident', which I was surprised at but didn't comment on.
Today:
A cousin of theirs has put up on facebook (yes I know, facebook is the root of all evil) that it was nice to meet up with DP and BIL. This was presumably when I was away over the weekend.
AIBU to feel betrayed? How can I trust DP when he has gone behind my back like this? FWIW I'm not banning him from ever seeing BIL again but it's the lying that has hurt me. If he has hidden this from me (he said he was working) what else is he hiding? If he is in contact with BIL then why hasnt he asked/demanded an apology on my behalf?
I'm seething at this. Cant even look at DP. He knows something's up but I dont want to open this big can of worms.
Help!