Hey Sweet, For what it's worth, i think the 'taking a vacation with the OW' - is pretty much standard script for Mlcers. I know mine did - and so did Alisuddenly's (just one other example off the top of my head). So, again, try not to take it personally. It's just them going through the process like they all do.
They always give some other explanation about what they are doing. My stbx had no money at all to travel overseas, so I almost believed his wacky story about having to go for work, but then i found out that OW had actually paid for him.
My stbx even went to the bother of reporting his passport stolen and getting a new one rather than coming home to ask me to get it for him (just another $600 or so down the drain...). Guess he felt too guilty/ashamed. Bet that made for a great time on holiday!
Please don't worry too much about how upset these 'discoveries' make you feel. It happens to us all. You are already noticing some change in how you react. Soon, it will bother you less and less to hear what he does. It's just a really slow process, and you can't try to push it along. You will get there.