Just yolo it and ask her

Only if you want to know

I would be worth knowing I guess. My mum told me when my parents broke up when I was 13-14 too. She didn't tell me everything though, I think I was old enough to understand parts of it. Was just really upset and mad with it. She should have told you why he went, I don't think that's something you can hide or just pretend it's normal. I think it could be bad for you.

If it's stuck on your mind then you have every right to ask and want to find out. I just wouldn't do it by text or phone. Much better to ask in person over perhaps a sensitive subject

I'm sure you are mature enough to handle the issues they had in their relationship. It's not going to change much but it doesn't hurt to satisfy your curiosity.