My car is a mess, I know, but is there a way to stop this?

There really isn't a way to stop that. You could 'fix' what has peeled, but that doesn't mean other places won't start peeling, if you know what I mean. The best fix would be a new paint job.

As far as fixing what has peeled, you could probably do some sanding and apply some clear, but if you haven't done paint work yourself, it would be a job for the pros.