All the ideas mentioned are good IF, your STBE(Soon-To-Be-Ex) is not intellectually and/or, mentally disabled.

My ex-wife could not handle the responsibility of being married. Maybe we were too young(we were both 25 when we got married), but it felt like she was always 'out to lunch'.

We had two kids, but I felt like she was third child. Yes, She gave birth(naturally) to both our kids, but mentally, I never felt like I could have a whole relationship with her.