I am a dark haired girl ( dyed ) and all of my boyfriends ex's were blond - other than me?

I guess I am a very self conscious girl, which would not be something most people would pick up on by ever meeting me. I used to do nude modeling and a lot of work that was at some points highly publicized. I am 22, and that happened at 20-21, I am now in a great job out of that whole modeling mess and I think I grew accustomed to hearing people other than my boyfriend worship me. I am finding my self to be so insecure about every girl around him yet a year ago, or 8 months ago I would have been so confident I would never have thought twice about any other girls. One thing that bugs me and I am curious what your intake on it all is, I am a dark haired girl I dye my hair dark from blonde, but my boyfriend has only ever dated blondes. Do you think there is a chance that it was a coincidence they were blonde or that perhaps he has a thing for them? What do you think? I mean I know in my past, I always dated men on there personalities and hair came second. I Really need to get over my insecurities of other females, perhaps its more deep routed then I think it may be.