I’m sorry you are going through this! I have found the phone is a problem in my relationship also — instead of talking over me, though, my ADHD partner just starts ignoring our call and starts clicking around eBay or Facebook. Our way around this has been to keep audio-only phone calls to only about 5 minutes, so we end them before his mind wanders. We also use FaceTime or another video calling app as much as possible, since he seems to find those more engaging. And instead of doing calls when we’re apart, we will text photos back and forth to share what we’re doing.
I realize none of these may work for you, but I hope you and your partner find a method that does!