Ex's Bestfriend

So this time last year I met my ex's bestfriend, and I fell for him. But I didn't have the courage to say anything until 2 weeks ago. Well he said that he liked me as well so we started talking, and had made plans to hang out the other day. But the day before we were supposed to, he said he didn't feel comfortable dating his best friends ex. Like 180 much? 
Oh and to add to that he said that he asked my ex if it was okay that we date, and he gave us the green light. I'm so utterly confused!!