Obsessed with my boyfriends past

Please help me! I have a very unhealthy obsession with my boyfriends past - i.e his ex-girlfriend and other girls he has been with. I dont know what is wrong with me, I am absolutely head over heels in love my boyfriend, he is everything a girl could want her boyfriend to be. He is kind, generous, loving, funny, really just perfect! And i know he loves me very much. So I really dont know what is going on in my mind. I am constantly thinking about his ex's - always looking them up online, asking my boyfriend about them (which annoys him, obviously) basically just trying to find out everything i can about them. And then when i do find a photo of him and a girl together, or facebook post from maybe 2 years ago with his ex-gf, i am devastated! It ruins my day and all i can think about is them together, and wondering if he was happier with them. My boyfriend doesn't know the extent of my obsession and if he did i am worried he would think i am a crazy stalker. I know i should just focus on the present, and he has told me a lot of times that he has never been happier in a relationship than in our one, so i dont know what is wrong with me! I am worried that if i keep thinking like this, it will ruin our future together.

you have a past too,if someone did the same thing would u like it,if you are uncomfortable just talk to a coun about this