I'll admit that this is partially inspired by the 'Bennifer' marriage but not about it.
And yes this has probably been done before but some topics are eternal.
My experience of this was when I met up in my early 40s with my divorced ex-boyfriend of 20 or so years previously.
We tried dating again but honestly I was so distraught when we split up (at his suggestion) even 20 or so years on couldn't kill the pain.
I'd moved on and no longer thought about it and at first it didn't bother me but as I grew to fall for him again it very much did.
I appreciate that people have problems - and indeed he did have mental health issues I was probably not interested in being young-but, nevertheless, I had to break it off because the pain was too deep.
Yes he seemed a much nicer person than he was before and I really loved being with him but ultimately the pain trumped everything.
I'm not looking for aibu here, it's how I felt about it and that's that.
So from my experience I feel getting back with an ex is a waste of time.
Just asking for others' experiences I suppose.