risk your current relationship for a past love and why?
It depends on the situation for everyone...
But here's what I think. If the ex was truly an ex (like you had a relationship with him) then, no, I would not go back to him no matter how unhappy I was in my current relationship. If the ex was a love interest that I didn't have the opportunity to explore and I was unhappy in my current relationship then maybe I'll get to know the ex(friend) a little better and see if we have things in common and can build on anything. Otherwise, if I was happy with my current relationship, I will not be risking my relationship for any ex. Things happen in life the way they do for a reason.