Hello and welcome to HCM,
Itching in the external genitalia (vagina in your case) after sexual activity suggests infection most probably fungal infection
Do you have a discharge associated with the itching?
If yes the discharge needs to be examined and culture sensitivity needs to be done.
If it turns to be fungal infection, a course of anti-fungals and anti-fungal ointment and/ or pessary need to be taken.
Besides discharge, urine also needs to be examined microscopically and culture sensitivity needs to be done.
Your partner also needs to be treated and abstinence is required till the time the infection clears away.
This could also be due to allergy
to the rubber used in condoms.
There are very quality condoms available in the market made up of very fine rubber.
You can try them.
If the problem does not resolve, avoid using barrier methods
allergy to semen is unlikely cause of itching.
Consult your gynecologist for complete examination and thus management.
Thanks and take care
Dr Shailja P Wahal