Help! I Accidentally Ended Up in an FWB Situation with My Ex—What Now?

Long Story short - So, my coworker used to be my girlfriend, but she broke up with me because she said I was emotionally distant or something (I was later diagnosed with autism). Now, somehow, we're in this FWB situation—I hang out at her place, we do stuff in bed and all, but I don’t know… it just feels weird.