No, I understand exactly what you are saying. I don't have a SO, but when I visit my father he now says, "Hey MAN. Hey buddy." As well as constantly interjecting son, he, and other masculine pronouns whenever he can. Before he would never do this! He would just call me by my name, which can be gender neutral. He is accepting of my transition yet is using those pronouns more than ever now!
It feels uncomfortable telling someone, "Please don't call me that," but its really the only way they'll kmow how you feel. Give them some slack, but if it persists down the road and you can tell they're doing it on purpose....well, you have to make a decision.