Quoting Chick+6!:" I will just throw this out there... I work 5 days a week. I am away from my 6 month old 11 hours a day ... [snip!] ... his reaction to you is a result of the time you're spending away from him at work. There is obviously more to this story..."
That's what I think. Probably has more to do with the time she spends (or doesn't spend) with him when she's home.
OP, you don't get to be a teenager you're a mom now. It's okay to have nights off, any mom needs that... but you don't get to be a teenager.