Just passed 5 years last week since my divorce. She left me because of my drinking instead of wanting to get me help. She grew up with an alcoholic step father, so she didn't want to be bothered with trying to save the family.
I didn't have a say in the matter, so I can only really say that I regret not being given a real chance to save my family. It still haunts my dreams (literally) and has been the lone trigger for the relapses I have had. So yeah, a lot of regrets and it's been the most difficult part of recovery to overcome, since I have to see her weekly. And I have to see her with her boyfriend when I drop my daughter off.
However, she's happy with her boyfriend she's had since the divorce. You aren't the alcoholic, so move on and be happy with someone who won't cause you heartache. Who won't put alcohol first. He knows he has a problem and he chose the alcohol over you.
Be thankful.