That's a pretty good overview so far. The whole thing started when he accidentally posted a pic of him in his underwear on Twitter instead of sending it as a private message to a girl. He deleted it immediately, and then lied and said he was hacked. Of course, he had sent other pictures in the past, and had what is being called "inappropriate communications" with women over the internet, and it all came to light. He stuck by the "I was hacked" for a few days before finally caving and admitting the whole thing.
Now Pelosi and many others are calling for his resignation, even though the people he represents don't want him to quit. He's even seeking "psychological treatment", which will probably only fuel his feelings of guilt and self-hatred and turn the poor bastard into a complete mess for decades to come.