Am I okay to get mad? He calls me "wife"

My SO and I have been together for 3 years and have a 2 month old. Sometimes he introduces me as his "wife" to people even though I'm just his girlfriend. I told him once that I'm not his wife until I have a ring on my finger and he said "we live together we do everything a married couple does, we don't need a ring or a paper to be married" Uuuuhhh yes you do. Is it wrong for me to get upset about this? I kind of understood when he does this with strangers or at the baby's doctors appointment and people automatically look at my fingers and no ring lol. Today for Thanksgiving he introduced me as his wife and it irked me so much because it's lying and to FAMILY! Even his mom had a weird look when he said that.

UPDATE: We live in Illinois.