DazzleYou: I can answer this from experience.
Grab my shotgun out of my gun safe while the bastard was running trying to put his clothes on. He ran out of the house half naked. He was a neighbor so he ran home.
Then I turned and looked at my wife as he hit the door running and said, "Aren't you going to follow him?"
she said, "No she can explain."
I said, "I suggest you get your things and get out. Don't ever come back."
She packed up a suit case while I called the locksmith.

For a moment I thought your ex was with a woman...but I'm assuming you meant: "No, I can explain."
Have there ever been more lame words under those circumstances?