There is But One — Patricia Robins

Gina and Charles Martin are young and passionately in love. Their
marriage is perfect until Gina learns that she cannot have children.

Her husband's failure to understand the effect this has on her causes
her need for a baby to grow into an obsession. Gradually the young
couple's relationship deteriorates until they are little more than
strangers and their intense love little more than a memory.

Gina hopes first to adopt a baby, then to foster a child, before in
desperation seeking a solution outside the law...

A compelling classic romance from the inimitable Patricia Robins, first
published in 1965 and now available for the first time in eBook.