If your friend did the breaking up, its more socially acceptable to date your friends ex. Under all circumstances, it would be a nice idea to just ask your friend politely if he or she is okay with it. He or she may still have feelings for the ex, even if it happened a long time ago.
Is it okay to date your best friends ex?
The unspoken rules of girl code imply that its basically never OK to date your friends ex, especially your best friends former boyfriend. Unless you value your relationship with a guy more than your friendship, respect that your friend may not be thrilled you want to start dating her ex.
Can you hang out with an ex as friends?
RELATED: Is It Okay to Stay Friends with an Ex? A superficial friendship is fine, says Snyder. Basically, this one is NBD because its about as innocent as it gets. Its a way to let him know you still think of him, you acknowledge him, and you remember this important date, says Greer.