Yeast infection

Ula
I always seem to get them after sex sometimes. Me and my bf had sex twice and I was fine then the 3rd time being lazy he licks his and wipes my private area to make it wet and the next day I felt itchy. He does this often and soon after I get an infection. He gets mad that I constant get them but it's not like I'm asking for one. What should I do and what does it mean when I get them frequently?