A journal is a good idea for everyone here but don’t use it just to keep track of the wife’s screw-ups. Keep a diary of EVERYTHING.
Because when you happily whip out your log of her screw-ups, she will respond with a litany of all her good qualities. You need to address the pros and cons for BOTH OF YOU. Be honest and the court will pay more attention to you than if you use the log with the attitude that your s$%# doesn’t smell (pardon my french).
I keep track of how both of us interact with my daughter (which is easy – my soon-to-be-ex doesn’t do anything). I note factors that may have a bearing on why we did or did not do something. I write in it about once every 3 days in pen (which seems to have more credibility than if you type it in the computer).