I've been with my boyfriend for three years now, and several months ago I found out that he was flirting with someone else on Facebook. How much further it went, I don't know, but he tells me that it didn't go past Facebook. Sometimes I still find myself stalking this girl online — not good, I know, but curiosity gets the best of me. When I do, I start to feel uncomfortable again and end up picturing them together. I know this isn't healthy for our relationship and I've decided that I want to get over it, but how do I start? Is it just a matter of time, or is it also his responsibility to help me through this?