Without knowing any of the specifics of your particular case ...
In general, this seems like an exceptionally bad idea. She's an EX girlfriend for some reason; proposing to her is basically saying "let's ignore all the problems we had that made us break up in the first place, and bind ourselves in a legal contract that's difficult and expensive to get out of and will socially stigmatize us when the relationship inevitably fails again, because how could that possibly go wrong?"
Chat with our AI personalities
If its for love and you feel he loves you but isn't showing it then yes To win him back, NO!