So 3 of us (me, my ex, and my friend) go to the same class we are all 17 years old, and recently, my gf(I'll refer to her as N) and I broke up.It was mostly mutual, but i feel like she broke up with me more than i broke up with her and i still like her.                   
                                    
So it's been 4 months since we stopped dating and in that time i noticed my friend, who we'll call P, getting closer with her, which is fine it's okay for them to be friends i can't tell him or her who to be friends with.BUT here is where i see some red flags, from time to time i see him being flirty and getting closer to her, he spends time with her friends who he said he hates multiple times while i was with N and even after that.              
                    
Now i know N would never be with P, she pretty much looks at him like at a gay friend and i'm sure of it, i know things can change but i'm pretty sure she is just friends with him and will continue to be.But my friend seems like he likes her, i asked him a few times, and was told by him that my 2 other friends already told him to cut that stuff out because they thought it's not cool.What broke the camels back was him getting very close and touchy with her, she didn't reciprocate it and moved a little.Now that got me mad and i told him that if he continues with that stuff we couldn't be friends and asked him to cut it out, he got very defensive and kept saying he doesn't know what i'm talking about and that he is just her friend even tho it doesn't look like that to me or to 3-4 other friends.          
             
Since then i haven't said a word to him, basically ignoring him.He didn't say anything either in last 5 days and continued talking to N, looks like this friendship means very little to him.I'm gonna talk it out with him if he says something first, but i'm not going to be the one to talk to him first cause i feel like i'm in the right here.             
                  
             
TL;DR:My friend of 2 years, started getting closer to my ex which who i broken up 3 months ago, both me and my friends noticed this and I talked to him about it, he got very defensive and i started ignoring him.Friends says i'm overreacting because we've been friend for 2 years which makes me think that *maybe* i'm the asshole, what do you guys think?                  
                        
             
AITA?