i'm actually friendly with my ex'es. in fact, i'm pretty close with one in particular. i do pray for him regularly, especially because of some of the stuff he's dealing with currently.
once i care very deeply and love someone, it's pretty tough for me to stop caring about them, as a person in general. i always want them to be well and happy. it's not all rosy right after the beak-up, but after some time and space, there's only been feelings of goodwill.
that said, i don't know if my feelings would be the same if i had felt betrayed or cheated on.
for the most part, i've prayed for exes, not regularly, but when they come to mind or i am aware of something going on in their life.