A couple of things come to mind... 1 - You may benefit by attending Codependents Anonymous meetings.
Co-dependents Anonymous 2 - The book,
He's Just Not That Into You, opened my eyes and ripped me out of my own denial about how someone had been treating me. I, too, made excuses -- "I can see his inner beauty, He's getting his doctorate and is just SO busy, He was adopted so has these issues (that I can help him with!)" Etc., etc. The healthiest thing I did was walk away and not look back.
I'm no longer in "friendships" where I allow myself to be mistreated AT ALL. There are too many supportive, like-minded people out there. I can love the person, let them be where they are - but I don't have to spend time with 'em.
I used to get confused, and think that if I cared for someone, I should stick with them, so they could experience unconditional love and heal. I can love them, and make healthy boundaries... sometimes, that means not seeing them or talking to them.
It sounds like your decision to do an intervention and provide information was a loving act. Can you do that, know you did what you could, and let go?