Answer her

"Oh, hey," I managed to mumble. "I was...uh..just weedeatting the fence."

"Thats the funniest looking weedeatter I've ever seen," she said, still laughing.

"I was just checking behind this bush...to see...uhm...if I needed to weed eat here," I lied.

"Why don't you come over here and check my bush for me."

I just stood there. I'd done my share of jacking off to porn, and I've even jacked off on webcam several times, but I've never really cheated on my wife. It still wasn't too late was it?