Would you date one of your current b/f or g/f's friends or ex's.
Hopefully you know what I am asking!

Me, two things I have believed in, no matter how hot/sexy/good looking they are:
1) never date a mates girlfriend - g/f's come and go, but friends can be for life.
2) never date a mates ex g/f - most probably done in revenge and can ruin your relationship with your mate.