This is terrible, @Angran1. This affair is but one more shit sandwich that he has been serving you. As he has told you, “His wants come first.”
Like @TwistedWonder, I too wonder if this OW is the Ex Wife who has no clue you exist, or his Ex Fiancée whom your Partner keeps in frequent contact with. You have written numerous threads about your unhappiness with his callous disregard of your feelings and boundaries.
For 4 years he has adamantly refused to tell his Ex about you. He said he would at 2 years, but reneged. You feel humiliated and have issued ultimatums, but nothing changes. His lame excuse is fear of repercussions regarding contact with his non-verbal teenage son whom he sees regularly. You swap out living at each other’s homes, but you are expected to clear out of P’s house when his DS comes over. If you are there during their FaceTime visits, you cannot make a peep or even cough.
He fully supports his Ex financially, emotionally and practically. When she says jump, he asks how high.
Regarding the ExFiancee, he disregards your discomfort with their level of contact. In my view, he enjoys the gratification of having a harem, and you are the low man on the totem pole.
@Angran1, he has treated you with massive disrespect while you’ve given to him abundantly. It’s mind-boggling that you would even consider staying with this lying, cheating rat and settling for more of his shitty crumbs. Surely this is the nail in the coffin.