I've not really got any ex's so it's hard for me to put myself in a hypothetical situation, i suppose i would have some issues with it but it wouldn't be anything i couldn't get over adventually. I suppose there's always going to be some tension depending on how they broke up, but i can't ever see why someone should just say "I can't, you're my mates ex". It's just stupid. But then again i'm coming from a different point of view with the whole relationship thing, i don't put anything before a relationship, distance, work or friends, where as other people will be the opposite.