my vagina itches

idk what to do. I have only had sex with one guy in the past month. he's my ex but we still do it regularly so I would think he would be clean. but I'm on my period and the itching started today( today's the 3rd day of my period) why am I itching? is it irritated from my tampon or something? I have no idea but it's red and itchy😩 I can't tell my discharge bc of my period so I'm not sure what's going on. any ideas?