>He is a great partner and good father...

OP, I know you are only saying this because you feel trapped and like you have no choice but to make yourself content with the situation you are in.

Someone else said to gather evidence of all the expenses you have been paying for. Please do so and then talk to a lawyer. Don't just assume you have no case and your little one will be taken from you. Also, it doesn't sound like this man wants the responsibility, considering how he has been preparing for an easy separation. I think he is taking advantage of you while he can but if you leave he may very well wash his hands of both you and your baby.

It sounds like you are also grieving some of your hopes and dreams, marriage and a loving little family.

I highly recommend the book Should I Stay Or Should I Go? A Guide to Knowing If Your Relationship Can--And Should--be Saved by JAC Patrissi and Lundy Bancroft. Get it today, it will help you find the path forward that you're looking for.