Hey roo I know that feeling when your child leaves. My S goes for a week and it’s still tough sometimes. The first time it felt really bad but it gets better.
I don’t know if your XW will ever communicate why she left but in your sitch it wasn’t because of you mate. It was her own issues that she largely hid from you til bd when she couldn’t cope anymore. I think I remember you saying she had childhood issues too. In my sitch I got many many reasons some of which I understood others were just selfish and weird. I think the hurt comes from not being given a chance or an opportunity.
Give it time mate
Me: early 40's XW: nearly 50 T: 15 M: 5 BD: Jan 19 S:10 SS: 22 SD: 24