OK think how you would feel if your bf was like this with your friend M sounds like not such a great guy if he'd try steal his friends woman think if your friend was flirting with your bf what would you think of her?( I'm sure not how nice person she is) I think your just enjoying the attention from someone other than your boyfriend because its 'exciting' not so much that you want him more than your boyfriend because there are problems maybe your holding negative feelings for him you need to think about your problems and either let it go and work things out because its bad to have serious thoughts of others and not fair on either of you or move on probably not with m.
I hope everything is OK its good you could ask on here.
I hope everything is OK its good you could ask on here.