I'm not going to have intercourse with my wife.
I wonder why you don't want to have sex with your wife.
I am too old for kids, I already had my share of child-minding.
I understand that you don't want more kids, but not having sex with your wife to prevent that is unreasonable. Have sexual relations with her or it will destroy your relationship.
My wife is the problem, actually. I don't find her attractive anymore while pregnant and vice versa.
There comes a time when you have to hold back while your wife is pregnant. It is not that important to have sex all the time, just be ready for it when you are both in the mood. It might be after she has this future baby.