To recover the memory of being nurtured, of course! Breast-fed men make better lovers, and better husbands.
The health (or lack thereof) of a man's relation with his mother will determine the kind of husband he is/will be. They don't call them Mama's boys for nothing!!!
A man is also interested in the size of a woman's breast in order to determine if she can be nurturing to the children she will bear him. It's all about immortality through reproduction.