To add to my previous response - my tactic for not making the same mistakes again is to not have sex with a potential partner until I have spent a long time getting to know her, becoming close friends until I am confident the relationship is good and healthy. If I have sex with another unsuitable partner, I'll be stuck again until she dumps me, as is the case in every relationship so far - as I said, I have a weird issue that I irrevocably bond with someone as soon as I have sex with them.

Edit: I'm conscious of the fact that I might be single for a looong time!