Falling apart

So hubby and I had a beautiful baby boy June 1, 2016 .. Need I mention he's a great at being financially supportive. His mother came to visit for 2 weeks. The moment she came his attitude changed a whole lot towards everyone. Mainly towards me. He's been more defensive.. He's even embarrassed me in front of his mother several times by raising his voice over something very minor. Now it's like he's more willing to just say whatever when he wants since his mom is around. His negative energy is now running off on me and I hate it because I feel like I'm being a grouch and not very welcoming to his mother. I've sat down and talked to him about it and he doesn't really see where I'm coming from. I don't understand the sudden attitude now that mommy is here .. Anyone gone through this ?