So he walks out because he feels like it and if he feels like coming back, he will, and if he doesn't, he won't?
That's not very nice for you, is it?
Won't you just be on edge waiting for the next time he feels like walking out?
If nothing else, he'll have ensured that that fear stops you from questioning him again. Won't he?
I know it's heartbreakingly painful, I know it is. I know that all you want is for him to fold you into his arms and tell you he loves you and he'll never hurt you again.
but step back and look at what he's done to you.
What makes you feel that he can do all that and THEN get to be the one to choose whether he comes back or not?
If he wants to, and if that's what you want, then that's your choice. but make it BE your choice. And make sure he knows that that is what it is.
At the moment, he's walked out on you all. And he's telling you to leave him alone while he chooses. And then he'll choose. And you'll be expected to accept whatever choice that is. And maybe that choice will be to walk back in through the door and pick up where you left off. With a lecture about how you behaved and how you must behave in future in order to avoid this. And possibly you'll feel it's your fault. And perhaps you'll change how you behave because you're afraid he'll go again.
But you'll still be waiting for next time. You'll be the one not asking the question, in case he leaves. You'll be the one making sure he's happy, so he doesn't leave.
But what about you?
If he wants to come back and if you want to let him, please talk about it and please don't let him make you the bad guy and list all the ways in which you've got to change.
It'll be a horrible life for you.