I am not sure about the Easter "party" but IMO I would at least do the Easter church thing. I know you W is doing some cake eating but it is a special day and the kids deserve to have you around, especially since the separation is so recent. Put everything to the side for a moment and enjoy it for yourself and the kids.
Afterwards, re-enter reality, stick to your boundaries (e.g. parenting plan, no contact, etc), move on, and DB if you so desire.
