She's got a lot going on. This is not about you. She's made it clear, this is all about her. She's being selfish...and by your own admittance, you were first.
There could be a certain amount of "punishment" here she's doling out to you, but I also think she is very very confused about a life with or without you. But I really don't think she's looking long term at OM. If she really really were, she would have told you to go screw yourself when you asked for less time between your children and OM. I know I would if I were very serious about someone and my H made noise about it, I would say "Deal with it because this guy is going to be around for a long time."
Calm down. You're really doing better than you think. And these amazing wonderful nights you THINK they are spending together probably are not happening.
