Womb With A View

My friend constantly talks to me about her baby on the way and asks me to help her pick out furniture and clothes for it. This is very painful for me because my husband doesn't want kids and I agreed not to have any. I didn't realize I'd have this deep longing for a child, but I love him and am not willing to leave him. I also have a hard time asking for things, even if a person is my friend. How do I tell her it would be better for me not to talk about this so much without making her feel bad? ...