I’m very glad my parents divorced when I was still really young. I didn’t really care, didn’t really realize what it meant, and just grow used to it. I can’t even imagine how those two have ever gotten alone. About the only memory I have from them together is each one of them pulling one of my arms arguing about where they wanted to go. It’s for the better this way. So I would say, get some relationship counceling if they haven’t yet, and if that doesn’t work then I think a divorce is better than arguing all the time, as that is also (/more) terrible for a child’s upbringing. I experienced that with my mother’s new boyfriend who lived with us for five years or so.