It could very well be to throw it in the face of OW, especially since things are not going well. Perhaps he is trying to make her jealous. But that is all mind reading, so no point in dwelling. Of course your H is angry with you. But I bet he is more angry with himself. His anger comes from the realization that you are no longer 'his'. He has wanted to have his cake (ok, lets call it cupcakes since there are many) and icing as well. But make no mistake, at that party he was definitely second guessing himself. Your job is to continue to make him second guess now that the party is over. You did well by validating his statement about you kissing someone in front of him. You definitely could have taken that in the pot calling the kettle direction, and I think you showed tremendous maturity and restraint by validating and understanding. So kuddos.
I know it goes back into mindreading, but remember, a guy dating 2 or 3 times a week with multiple partners is extremely selfish. In other words, these are not going to be lasting relationships, as he is not offering anything by doing this that another woman is going to jump at long term. Perhaps OW has already seen this. He is looking to have his own needs met, pure and simple. I would not even suggest he is looking for your replacement so to speak but a bandaid for his journey. You definitely seem awesome to us here, your personality comes through in spades in your postings, so yea, it seems replacing you would be an uphill climb for him. But there is a flip side you may want to consider if you are really wanting to dive into what 'may' be going on in his mind.
*adult theme disclaimer* What your H is doing is something quite honestly I used to do to some degree, and have had thoughts of doing many times these past few months. Getting 'laid' is easy. Finding someone to 'make love to' is much much harder. Let me explain the hows and whys. Any decent looking guy or girl can find someone to have sex with fairly easy. Especially if you seek out people who are less attractive. In fact these are usually the ones I would seek out for flings because they were the ones I would easily be able to move on from and as cold as it sounds, it was much less effort. So the upside is ease of getting in and out. The HUGE HUGE downside is, and most guys will never talk about this, is that it leaves you with a huge void, often bigger than the one you are trying to fill. By that I mean not only is it an empty meaningless relationships, but if FEELS empty and meaningless relationship. Once the sex is over, you cannot wait to get away. Where as when you are with someone with an emotional connection, you want nothing more than to keep being with them. Your OW was probably the one he had that emotional connection with, at least at first. The other ones are the empty ones. By virtue of his actions with the empty ones, and assuming OW knows, his R with her is all but doomed. Unless she just has zero self esteem in which case it will be doomed later.
I am telling you this because my guess is that your H is not trying to replace you right now. He IS probably taking advantage of the fact he has the time (not the moral authority) to sow his oats with other women. I have thought about it all summer how nice it would be just to go out with one or more and get the physical affection and even temporary emotional fulfillment. However, what stops me is I know once the deed is over, I will be left filling as empty, if not more, than before.
Me: 42 W: 32 Married 7 years together 8.5 S1: 7 S2:7 Bomb #1: 09-16-13 Recon #1: 11/13 A discovered 04-03-2014 W filed D 05-19-14 but never served me I filed D 12-02-2014 S 05-31-14 Divorced 5-19-16