I usually use their name. If I need to describe the relationship, then "friend" if they are my friend. If they aren't my friend, I don't have a reason to describe their relationship except on this board generally. In that case, it's back to a name and titles are avoided.
But-I find titles very difficult most of the time. Particularly because GG and I have filtered through SO MANY roles in each others lives and sometimes by the day...
Currently we are broken up in the sense that we are not sexually involved at all (and haven't been for months). But we are still roommates, coparents and we still love each other. We're still friends... but to use one of those labels suggests to other people what we WILL be and that is undefinable. So I just call him GG.
"Love As Thou Wilt"