Still friends with one ex. Can't stand most of the others. The one that I'm friends with apologized for screwing around. It will either happen, or it won't, there is no point in trying to maintain a relationship with someone that treats you poorly.
I believe it can be tough because there are always feelings that are going to exist but if you are responsible about it, I believe it can work. It's generally not an issue between you and the ex, the issue falls on the shoulders of your new partner and their feelings on the subject.
Friends with 2 of 4. Whether you can be friends really depends on how you both feel. If one still likes the other, it won't work. You both have to be completely over each other, or very good at burying feelings. They're your ex for a reason
I'm friends with one of my ex's. 2 I've completely cut off because they broke my heart and didn't give a shit about it afterwards. I don't need to be friends with people who turned out to be such cunts.