Sounds like an unusually mellow cat. I've had affectionate cats, but they were very selectively affectionate
This cat was a very affectionate cat...but you are right, he was selective about who he was affectionate with...he was originally my sons cat, but when my son took a year long around the world trip, he asked me to take care of his cat for that time...just a few months later, I sent my son an email, telling him he could not have his cat back, me and the hubby had fallen in love with him...
When my son returned from his trip, he saw how happy and content his cat was, and agreed, that he was probably better off with us(being that my son was always on the go, and me and the hubby were more settled)...so the cat stayed with us for the rest of his life...He was quite a sweetie...