Not angry at all. Just pointing out that becoming involved with an additional person is not really as easy or simple as it sounds to say you're "adding" someone
to the two of you. There are four dynamics among three people in relationship. It would be you & hubby, hubby & gf, you & gf, and all of you together. Complex and in need of clarity, awareness, and attention. And it doesn't sound like it's something you really need to be dealing with right now. Also sounds like your husband is rather stubborn and doesn't want to be told what to do by anyone, and that's not good with what you have to focus on.