Need to vent!

I’m a single mom of two little ones, I’ve been separated for almost a year I was with my kid’s dad for 8 years. We split up bc I found out he was cheating on me with a coworker of mine..well ours. He’s also my boss to this date. Anyway, fast forward to now I just found out he’s now dating ANOTHER coworker and also his employee. I’ve been over the situation for months now but I have certain triggers like this in particular that just bring back all the rough times in our relationship. I honestly feel so disrespected bc this girl talks to me on the regular and knows the situation between him and I. She’s a snake! I feel like as a woman and coworker she should’ve came to me fist... but obviously he told me about them he said it’s been a few weeks now, should I wait for her to tell me or should I call her and demand an explanation?