NAB, you don't need tarot! What you need is to stick to your wise decision and walk away. Whatever the OM does in response to your happy NY text will hurt you. You see that, don't you?
If he texts you back, you will see it as a sign that he really wants to be with you, and therefore you will ache for the lost relationship you were cheated of.
If he doesn't, you will feel the pain of knowing that he didn't need to contact you on this 'special day'.
There is no half-way-house here. You have to break contact and walk away completely. You deserve to be happy, and the only way you will (eventually) be happy is if you throw yourself completely into your marriage.
Also, your DH deserves to have a wife who is 100% committed to him, and no matter what you say, right now you are not. Maybe 90%, maybe 95%, or even 98%, but not 100%, because you are still saving a part of yourself for the OM.