This is how I see things.
I could never really see the benefit of keeping an ex as a friend. Yes, they may be cool people. Yes, we have history but I hold onto the memories, not the relationship. Maybe it would be a bit different if I were single but I doubt it; I've always felt this way. How would my significant other feel if I still had an ex lingering around. I can say we're friends and all that jazz but is that really fair to my SO? Probably not...I don't think I would like it. I don't think the dynamic of a romantic relationship changes when you take away the sex. I can see it now...my ex from college comes over, I tell my husband we're going out to the movies and I'll see him later. Yeah right! He would lose his shit. If I'm going to have a friend, male or female, I need to be able to interact with them in the exact same way.
Friends on the other hand that's different. Like some others, I've had some pretty good friends over the years. They've reached out to me, but I haven't really be responsive. I need to get better at that. I can't tell if they are just being polite and are saying hi, or if they want to resume the friendship. I can never really tell...so I think that's the reason why I'm a little cool...I suck at making interpretations. But exes?? Phhht they come a dime a dozen trying to seek a "friendship". I think their full of shit mostly! I think that's my cynicism kicking in.