I wouldn't pretend about having a person sending you a stuffed animal or anything romantic. It * will * backfire. Your H will just use it to justify his own actions. If he was out of the house and with OW completely, then that is a different story (though I don't like being that deceitful).
There is nothing wrong with sticking something on your dash, though - maybe in your back window. Leave a sexy bra in the back seat. Okay, a little deceitful - but let her wonder if she passes by the car. She's been a witch, so no reason not to play with her mind a bit.
Don't bend over backwards for him all the time (unless, of course, its for sex and make sure he uses protection). He's got his cake at home and his cookies elsewhere - let him work for the cake.