My boyfriend is acting distant and I don't know what to do

Hi you guys I'm not sure what to do about my situation. Background: Been with my bf for over 2 years. Our 3 year anniversary is coming up. He's lovely, kind, sweet, nice, funny, smart, and pretty cute. So, lately, he hasn't contacted me as much as he used to, he doesn't get excited over much of anything I suggest or what I point out, or my jokes. I feel as if he doesn't care about me much anymore. There was this girl that he was talking to at one point and he leaned all over him in front of me but he didn't say anything to her. I confronted him about it, told him how I felt about it and then he said ok but then he continued to talk to her. He has flaked a lot recently I confronted him about that and told him that he can't do that and it makes me trust him less because of that. Then he ended up telling me that he was stressed. I'm thinking, "are you kidding me??".