Jeanna, I think you're being very smart to opt for the "in-between" place of going back part time for a week and then continuing full time if all goes well. You're letting Rod know that you care enough to start gradually but you're also taking care of your own needs, which are so important! I laud you for trying to find a middle place to land; you're conscientious and caring and also wise enough to know your own needs and wants.
There's no perfect answer for this, but you are clearly doing the very best you can, and that's all you can do! Hang in there, and good luck to both of you with this big transition. It will go all right, I feel sure.