If your partner had herpes genitalis about three years ago, she may still be passing the virus in the genital secretions, more so during the attack of herpes, which may not be visible on the exterior genitalia. If you had not used the condom consistently and regularly during sex, there is possibility of you contracting herpes. The problem of rashes in the groin area and genitalia could be herpes, but other possibilities like candidiasis, contact dermatitis etc. need to be ruled out through a clinical examination by a dermatologist.