I have known people both male and female who have done the FWB. They act like it's the best thing ever. But, personally I wouldn't recommend it to anyone. Unless, you absolutely do not WANT to be in a real relationship. I think the FWB will block your blessings. I know that sounds corny, but I think it's true. Your soul mate could be checking you out, but every time he passes by your house that FWB is parked in your driveway. There's another name for it....c***blocker. Bad news. I say enjoy your single time. Get spiritually fit, whatever that means to you. Get a new hobby, maybe one that brings in extra cash. Have male friends to hang out with, to introduce you to some nice guys and stuff, but no benefits.
Oh, especially not with an ex. Somebody would probably catch feelings and then when its over, bad blood.