Cold sores, or fever blisters as they are sometime called, are caused by certain strains of the Herpes virus, especially Herpes Simplex type 1.
If your partner has a cold sore, avoid physical contact with the lesion/s – including oral sex – as you can easily get a cold sore on your genitals… You will not be happy with its miserable painful feeling nor with the virus which has now taken residency in your body. And, it may easily give you painful intercourse (dyspareunia) or even vaginismus. Ouch.
It is okay to say NO to physical/intimate contact when your health is at risk.