I need a blunt way to end things.

I feel absolutely horrible as I was the one who fell in love first, as time turned out when she finally loved me back (2 months later) I found out I'm an avoidant attachment type despite being nothing of the sort before. I lost the feeling and I don't want a relationship anymore. If you were in love with someone how'd you want things to end? I don't know what to do but I know it'll only cause complications if I keep a relationship I'm not happy in going. This is a throwaway account so that it cannot be traced to me. All in all, love has apparently been absolutely ruined for me by past relationships and I want to die alone. Any advice is appreciated.