@Save wolves,
If suddenly seperated by a significant distance, can be easier to just end things rather than have both of your pining away from each other. Could be easier for him to not have you 'out there somewhere' open to being with him again if that isn't possible or practical. And instead of confirming such a desire to you, pretend it's over and he's happier.
If I had to move and that would effectively end a good relationship, I'd rather go on with the impression things were over, than still going on but we can't be together any more. Sort of like wanting to burn down your hcildhood home when you move rather than anyone else ever living there. Or maybe that's just me.