I have been dating my b/f for a couple of years and in general we get along very well, but there is one thing that bothers me a lot. He knows a girl (which he likes) and EVERY SINGLE TIME he sees her he gets an immediate hardon. Even a couple of times that he saw her on a photo he got hard again - and he stays hard until he jerks off. Of course I don't feel well pleasing him when he gets like that over another girl, but on the other hand I know that during that time he must think about her. We have had several fights over that, but he says that he can't help it. Is it trully just happening and he can't help it or there something else going wrong. I mean, every time and only with just this girl?????