Why do I keep having sex with women who are married or have partners?

im 28 years old and during my time about 80/90% of my sexual partners have been attached, married, engaged or just going out with someone, nearly all have had kids with there other half aswell, I want too meet a girl who is single but just seems I always end up with someone who is attached! I just dont understand why I do this, I dont feel like its a concious decision of mine too go away with married lassies, it just always happens

Maybe you just prefer their experience in things....Or maybe its a conincidence. As destiny would have it.