Its better you tell him o..though 90% of cheating partners do not disclose their status to their spouse. I have seen cases of married women n men that goes to take treatment n yet they keep it away from their spouses thereby allowing those ones suffer in silence. This behavior is allowed due to the medical ethics that allows the victim to state it to whoever s/he wants to tell it to and also keep it away from whoever s/he wants. Though if there is real love and the victims partner is still free,s/he is meant to disclose it.