Your response of not wanting the world to know that your partner was cheating is one. Some folks feel embarrased or ashamed in some way. Some may even feel that their partner cheating on them reflects poorly on themselves. I think this is probably more often in cases where the individual has low self esteme.

But there is another response. One of a feeling of righteous anger and a desire to tell EVERYONE about said offending partner. Some folks get significant psychological benefit from venting. And what is a more impressive display of venting than telling the WHOLE COUNTRY what an asshole the guy/girl is.

I think both responses are valid responses. Just different ways of responding to the situation.

Me, I have had a couple of girlfriends cheat on me. When I found out I simply told them that we were through and walked away. Nothing to discuss really.