Well... as has been said, it's probably dependant on the cat's personality. You can TELL when an animal is trying to get away with something.

But the real bottom line is --- Who cares if the cat is expressing it's dominance by sitting on you? If they want to snuggle, and you want to snuggle.... SO?

Eleanor Roosevelt stated that "No one can make you feel inferior without your consent."

So if you don't feel 'dominated' obviously you aren't. The cat is too small to REALLY dominate you. You can let it push you around a bit, but that's your choice, and it's up to you if you want to do something.

I think your boyfriend is jealous of the cat. Some guys just don't want to share your affections/attention/physical contact with ANYTHING.