Is it ok to date ur close frends ex?

Ok. So My friend went out with this guy she knew i was thinking about going out with but i was mor than likely gonna say no cuz we r good frends. They only went out for like a cupl weeks (& i was a lil jealous & kinda wished i had said yes wen he asked me :/ )and then she made out with another guy while they wer still dating and then she broke up with him. Now she has a new boyfrend and says she doesnt even think about other guys cuz shes falling so hard for this new guy and doesnt like her ex at all anymor. does this make it ok for me to date him?