I have doubts about feelings of my boyfriend

I’m in a pretty awkward situation. The point is that my boyfriend J. kept in touch with his friend L. whom he liked for a long period of time. The story is quite complicated indeed. We started dating a year ago. Everything was fine and it is still okay right now. But I do worry and actually I do not know why. He has known L. for seven years. They met when they entered the college. He liked her, she liked him. But it seems like she needed more than that. I mean she is quite demanding person. She needed more than he could provide her. We told about the situation and he shared his feelings and thoughts. At the time we were discussing it he tried to persuade me they were just friends. Well, I do not believe in friendship between a man and a woman. It doesn’t work at all. He liked her but once she decided to get married a guy who was well provided for. It was terrible indeed. I mean it seems like my boyfriend felt depressed about it as he described me. Well, I could understand him. Anyway he could change nothing. They kept in touch and pretended to be just friends even though he still liked her. He had to accept the situation as it was. I do not know some details but everything was okay for her. She got married and communicated with another guy who liked her and who was faithful friend. He was ready to help her and support every single time she needed it. What could be better…for her? At the time J. suffered pretty much. He couldn’t control the situation.