Stupid things that make you mad

I found out in a not so nice way that my soon to be xh has a new gf. In fact that is where he is now. I don't care the fact that there is a new lady friend, in fact I urged him to do it, but the lying and deceiving instead of being honest there was uncalled for. He took ds2 trick or treating last night and evidently lied to him also, when the lady friend and her daughter joined them, he led him to believe it was a friend of the other people they were with...so I feel like the whole thing was a shamble from the get go, to so easily lie to your spouse, I wonder how far back this has gone?? It's just another reason why he is the stbxh!!!