The transgender reality TV star proposed to Jennifer Elia in 2009, but he put his wedding plans on hold to undergo surgery to complete the gender reassignment process.
Bono called off his engagement last year (11) but he is adamant the operation played no part in ending his six-year romance with Elia.
He tells CNN newsman Piers Morgan, ""Ultimately, the reasons why we split up had really nothing to do with that (sex change). It was (down to) issues that we were dealing with and just stark differences in the people that we are and what we wanted out of life.
""I have changed a lot and it's really the internal changes that are the bigger changes. I went from being really uncomfortable and kind of damaged for my whole life to suddenly not being that way anymore. As I started to feel so much better and my confidence rose, I (realised) I wanted to live the best life that I could and I wanted my partner to be able to kind of do that with me.
""There were deep-seated issues around substance abuse and stuff like that that had been really a problem almost since we first got together... We just wanted different things out of life.""
According to USA Today, Bono's former fiancee Elia is a recovering alcoholic.