If you're opposites, you complement each other; you aren't jealous. Just annoyance and fighting, as opposed to rivalry.
I don't like writing for myself to sing. I prefer to have other people's voices to dispose of in some way that they'll like or not like or flatter them or not flatter them. It's fun.
The actual making of the records obviously have everything to do with each other, because I made them one day after the other, alternating doing it.