I think everyone else has established why YTA. But can I ask if you feel insecure about being a stay-at-home mom? Are you threatened by accomplished women?

I was a stay-at-home mom for several years. We were also broke. I remember feeling really insecure about it and jealous of women who had high paying jobs and options. Parenting can feel like a trap. There was a lot of shame and it was heavy. Being a mom is something I have no regrets about, but those feelings can be hard to wade through.

The best way to deal with insecurity is to be vulnerable, confront what you are insecure about, and start working on yourself. Now I have a great career and don't struggle with the same insecurities. Being a SAHM is such a depleting experience in so many ways if you aren't finding ways to fill your cup. Have you pursued any of your dreams or worked on your talents or skills, or are you too busy telling yourself you don't have the time or energy?

I also hope you can offer a sincere apology to BIL's girlfriend. She might be a mentor and a friend if you can fix things.