My ex boyfriend is my new fwb. ?

There was this guy that I was interested in and who was also interested in me. We dated for like 2-3 months. We fooled around a bit. Over that time I fell in love with him. but it didn't seem like he had done the same so we talked about it. We decided quite mutually that we couldnt date because of restrictions on our relationship. And he said he still liked me and since we couldnt date he'd like me to be his fwb. I've never done that before so if you all could give me your opinions, maybe some guidelines to this whole fwb thing etc. I would really appreciate it!