What Causes Vaginal Itching After Having Sexual Intercourse?

I had protected and unprotected sex with my boyfriend three days ago and since then my vagina has been extremely itchy and today it stung when i urinated. Three weeks ago i had thrush and got given cream and a pill to get rid of it and it went but now seince having sex with my boyfriend its back again. Is it something from him, or it it me being allergic to him? is it more than thrush this time?