Hey Hey! [LONG POST]

So, there's this guy I've been talking to on/off for 4 years. We met in the most random situation. he was the officer over seeing my car accident when my truck was hit by a drunk driver...some weeks later, we just didn't stop talking...fast forward and we've established that it will just be a "FWB" situation because we both aren't in a place to commit even though we both want to..However, he begins to behave as if we are in a relationship (sleepovers, I love you's, marriage talk 🙄 and questioning me about things that he's "heard". He gets upset, we have a huge fight, and he pushes me away and I don't hear from him for like 4 months. Then once I get over that hurt, he starts texting and calling me again. then went ghost again (I know, shitty). This has happened at least 3 times...Anyways, he's back again calling me his baby and all the other mushy crap. And I'm completely numb to it and anticipating on his next flight...I guess I just want to know why he keeps coming back acting as if nothing has happened. He's even moved to a different area 4 hours away. My friends seem to think that he's a "runner" when his feelings begin to get involved but I would rather just talk about it then instead of him literally disappearing and wanting me to drop everything and everybody when he decides to come back and talk. What does he want from me?! ....thoughts?