Overreacting or Nah?

I would talk to him about it. At the end of the day he is a grown man and he must be feeling ok about it if hasn't told the woman he is feeling uncomfortable about the conversations. Ask him why the girl feels so conforted to tell him all that stuff. On the other hand I don't know what the conversations are about so it's hard to give advice.

It's a little strange for her to bypass you like that. I wouldn't say that you are overreacting. You have a right to feel dismissed. She could always speak to you both as a unit for advice. However, on the other hand she may not think you're interested. Maybe your boyfriend should offer your ear to her. This way, your presence is acknowledged as well as the continued ear to bend. Definitely talk to your boyfriend about it if it bothers you. Otherwise, your continued frustration will find a way to express itself in other ways.