FWB(Not sure if we should continue to do it)

My ex and I recently just got into a FWB(Friends with Benefits) relationship. And to be honest I don't know if we should continue it. We had been on and off for a few months and were engaged. As he had said he doesn't want the commitment part of a relationship and that with this it would have benefits without it.

To come to find out he saids that he's in a relationship with an ex of his that was before me. He saids that he loves her and me. And that he cannot choose between the two of us. To be honest I really don't understand what he means in all this? He also told me to just move on and let everything go which I think he means him.

If anyone has a suggestion or has been in a similar situation please share your story I could use the help