I was thinking the same thing as Tuffgirl on this. I think while we're in recovery ourselves, we have to find clear boundaries in order to find our comfort zones, and then as we move along our recovery there are some areas where those clear boundaries can be muddled comfortably. But therein lies the rub. Whatever's comfortable for you is where it's at!
My son has had a good r'ship with my ex(R?)ABF, and I think it's recently taken a hit since exABF has moved away. I still update them each on each other's lives, and the phone lines are open. I figure they'll strike a comfortable balance for their relationship at some point. It's not mine to manage, and I don't make 'helpful suggestions' about it, but I do openly talk about the other one in a positive light because I do love them both. My son knows ex(R?)ABF has moved away to try to get himself healthy and that there are no guarantees.