Having sex during periods comes with its own set of problems. The blood of menses acts like a medium for infections to thrive and this can result in swelling of vaginal, vulva and cause white discharge and itching.
So avoid having sex at menses. Or if you want to do it, use condoms so that the transfer of infections from one partner to another is avoided.
Next Steps
Many women feel wetness after sex, this is due to arousal and this is NOT a sign of any infections. Also at times during sex the hair around the vagina may get pulled and this irritates the hair roots which cause it to itch. Applying betadine gel wont help as it is not a medicine for every infection. If you wish you can get examined by a gynecologist and get proper treatment.
Health Tips
If you are having recurrent fungal infections, it could be due to it not being eradicated properly . Meet a gynecologist and get proper treatment to remove fungal infections. At times partner is also treated simultaneously so that the chances of getting it from him are reduced.