Should I insist on meeting OP's partner?

My ex and I split up for good 10 months ago, when our son was 16 months old. Co-parenting has been going surprisingly well, we are doing 50-50 and we text often about our son. I just learned that he has been dating someone new for the past 7 months - I discovered this on social media. I asked him about it and they are in a serious relationship, and she has spent time with our son. She sounds ok, she's a psychotherapist at a psychiatric hospital. It does seem outright deceptive to me that he has never mentioned this woman at all. I suspect this is for two reasons: 1) He knew I would be less likely to do favors for him if I knew he had a girlfriend (eg. cat-sitting, which I have done for him a couple of times recently) and 2) he probably hopes she and I will never meet because the history of our relationship might come up in conversation (some highlights - he was a raging alcoholic throughout my entire pregnancy, would flip out and break things when he got drunk, he threw things at me and threatened to kill me when our son was 6 days old and the police came and took me to a women's shelter, where I lived for 2 months with our newborn until he got sober and we gave it a second shot and I finally ended it 10 months ago when I was tired of dealing with the ongoing lies and craziness.) Anyway, it seems this new psychotherapist girlfriend is a good thing for him because the past few months of co-parenting have been surprisingly drama-free, he seems to have a better handle on life. My question is, now that I have learned about this other woman in my son's life, is the appropriate thing to do to get to know her? Should I ask that we all meet so that I can get an idea of who she is and how involved she is with my son? Or is that over-stepping and it's none of my business? Or should it be the plan to meet her, but later down the road since they've only been together 7 months? Is there any point to arranging a meeting? It's not like I could veto her if I don't like her lol. Just wondering what is de rigueur these days.