My boyfriend and I adopted our cats together, so there wasn't much issue there. Now, my bf has had cats most of his life, and knew more about how to interact them with me, but he did get a little frustrated with Apollo at times. Apollo was a new challenge for us both, being very stubborn and hyper and difficult to train.
I used to worry that he didn't like Apollo, or regretted us getting him, but now I often see him cuddling with him, playing with him, calling him, "My boy," and such. So clearly they did manage to bond. He's never gotten jealous of the cats though. The cats like us pretty equally, and I give both him and them equal attention. And he's probably a little relieved when Apollo gives me more attention because Apollo can be...demanding.
I think if anything, he's really glad we got cats because he sees how much I needed this. He's commented many times on how much happier I've been since getting cats. I just cannot thrive without some little furry companion to care for, and I was really missing my childhood dog since moving away from home.
No offense cooncatbob, but I would be very frustrated with your partner's attitude about that whole thing. I don't think I could tolerate that sort of behavior in a partner. It is a shame that she just abandoned her cat, but you are both probably better off without someone like that in your life.