You know it's a sin. You hate doing it. You do it and hate yourself for it as you do it. It disgusts you, makes you angry, and makes you feel filthy. You love the person and don't want to loose them. They ask this of you and you do it to make them happy. You want so much for your marriage to work. To last. To be blessed. You have a child with the one you love. No need to tear up a "happy" home. Right?
I am sorry for your situation, and hope that it improves.
If you are doing somethng that you know is a sin and you hate yourself when you do it then you need to stop. You need to get help and guidance and maybe counselling for the both of you. You need to say that you wont do it anymore and it will then be up to your spouse as to what they do.
if you know God sees this as sin then you need to put God first. Does your spouse know how you feel? have you told them this?
It kind of depends, too, on what you're talking about.