How do I know if what I feel for my partner is love or if I'm just with him because I need affection?

How do I know if what I feel for my partner is love or if I'm just with him because I need affection? I've been with my partner for two years now, and I've reached a point where I doubt the feelings I have. Sometimes I think I'm staying with him because I need to be loved, and he gives me that. Other times, I think I can still have the feelings of love I had at the beginning of the relationship. I don't know what the reality is.