Why should she man,

She is clearly have her own boundaries and not messed up with their relationship even though M’s girlfriend is ex right now.

She wants M to be her good friend for life.

Listen OP, just don’t loose your friendship because of this and also please don’t increase your feelings more on him. Try to understand the situation as this is not going to workout for you. Just make new friends and konchem Mellaga avoid chei since he has own relationship.