What would you do?

i am in this relationship w/ a boy who is a little older than i am and it seems like we always have problems....either he's accusing me of cheating on him or its just a big communication problem.....just today he tells me that some girl kissed him....now how ami suppose to believe that.....what should i do? almost everyone i know wants me to break up with him, but i do love him.....i just we are at different parts of our lives so its going to be a little rough....but out of all of the bad times, we do have good ones....but i also feel that i can't trust him because while im in school, he is doing only God knows what......Distress in need of some helpful advice!!!!!