How do you react when women flirt with your SO

I went to Red Wing Shoe Store with my SO and the lady working there was completely flirting with him. She pulled up his pants to try and help him tie his boots and everything. He gave me a look and I just smiled. I think it's funny when women do this but sometimes I get bothered too. Not with my SO but with them, seeing I'm with him and we have a baby together. I try and act like I'm not bothered at all. What would you do?