If you're pretty set on dating your ex's best friend, then date your ex's best friend. Just know that there is no way to win this one without someone getting hurt. Your ex and his best friend are going to have to hash out their own issues with one another, and yes, they may end their friendship. You can't stop that from happening.

As for whether you and your new boyfriend are happy, well, that's up to you two. Can you deal with the fallout of the potential loss of your ex as a friend? Can your boyfriend? Can you both handle the pressure it may cause between you?

We all make our own choices in life. If you want to date your ex's best friend, that is your business and not mine. But there are going to be unhappy consequences. And if you have a part in them, you have to own up to them.