OK mulled over this one, i say the above account is lies anyway.
She gets in car, confronts him about the previous affair he allegedly had whilst having an affair with him!
The argument descends into breakup and he wants out and says he's going back to his wife, she says fine im gonna go tell your wife you're a cheater.
He flips and strangles her in rage as of course it will ruin all his emotional ties with kids family and friends.
He panics and sends the text himself knowing he's in the sh't and in that irrational moment somehow justifies his response