Claire, you first have to figure out where your bad behaviour stems from. When you can identify the cause and address it, you'll be most of the way there.
Also, being 'selfless' is just boring. The guys I know all married women who will have their say when need be. Hubby ended the relationship with the girl before me partly because she only ever wanted to do "whatever you want sweetheart"
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.