Long distance FWBs are fine as long as you are getting plenty locally all the time. Keep a few long distance FWBs you meet during trips, etc so when you travel you have a network.
Having a long distance *love* affair is the dumbest thing a man can do. If you really "love" her (stupid is) then immediately move her local otherwise drop her. Better yet, don't ever get emotionally involved, far or near. If you analyze distance relationships you will find it is a safety device to insulate both parties from any real investment while creating an imaginary emotional investment. Also this type of relationship 100 benefits the female who receives full validation without any sacrifice.