Whats the most selfish act following unprotected sex?

Abuse, any sort: But requiring a partner to have unprotected sex as a condition of the relationship is utterly vile and also unmasculine. To conceal a sexually transmissible disease in this setting can get you prosecuted in some jurisdictions. Threats, verbal or physical abuse, ridicule, damage to property -- all of these happen; the other person should end the relationship and maybe get help from the law.