i love him.but i cant take it anymore.help

My boyfriend and i have been going out now for a month. We have been going out for a year yet we broke up for about two months . He didnt ask me out until last month. I should of listened to my friends and said no to him but i canr i love him to much. My friends dont like the way he treats me because in the end i am the one who always gets hurt. Everytime i walk past him in the halls he is just all over another girl, he makesno attempt to say hi or really have a conversation with me. He sees me walk by him , he knows i am there. It hurts me so much to see him go and do that. but i like him to much ot let him go. but sometimes that is always the right thing to do. Please help me with your thoughts.