Remember, this is all baby step stuff that you want to go forward with. 15 years...? What's an extra year starting at a nice, stable position.
Yes, he will have to "get over" his loss. He's an idiot... you know it... but... he's an idiot you'd be ready to keep if he got his act together...
But... first, he's going to have to want to try again...
second... you're going to have to decide if you want him back, this time... and then be clear that there will be no more of this nonsense from him... as you appear to not be too appreciative of it...
again, not to think too far ahead here... but if it finally comes to a point that your M is back to good shape, you keep the changes going and the two of you are meeting the needs of each other and growing together in healthy ways...
so yes... giving him a taste of what he may be missing in the future if he does not choose this mission... is a great idea... no candy for him at this time... he needs to do his own work and show that he wants back... but he is more likely to want back if he knows what he'll be missing...
