What Is Causing My Vaginal Discharge And Itching During Pregnancy?

Hi, I'm 4 months pregnant, I recently started having a yellowish discharge coming out my vaginia all the time and this will cause my vaginia to itch. Also when I have unprotected sex with my boyfriend it will hurt a lot and burn, and he will complain that his penis itches after we have sex. Can u explain the cause of this and is there a cure?