I agree with Kat. I would not send the card. If he is hell bent on getting the divorce he would never see the card as anything other than you being clingy, trying to make him feel bad about what he has done and trying to manipulate him into changing his mind.
From personal experience I know it [censored] to be the only one who wants to save the marriage - but at some point you have to start simply focusing on saving yourself. Best to you.
