Childish behaviour ?

There's an older man I'm interested in. We've been romantically involved for a little while and we work together. He's actually never been sweet to me. He just makes fun of my age. I'm 20 and he's 28, and makes jokes in reference to Chuck E Cheese and what not. It irritates me and I'm not sure if I should continue to be sexually involved with him. Is him being rude the only way he can show interest? Or is it just plain disrespectful ?