My own head cannon is that she never actually loved him but was convinced by Obi Wan to play the role to perhaps act as a stabilizing influence.

But soon she discovers that her erstwhile side piece is a psychotic man-child with the powers of a minor god. Now things have spiraled out of her control. There's a legitimate fear that, it rejected, Anakin could become unhinged and lose control.

After a few years in a loveless marriage she found herself pregnant and, like in a lot of actual abusive marriages, latches onto that as a means of preserving a relationship that should have been allowed to mercifully die.

This is the only way I can reconcile the terrible performance from an otherwise exemplary actress. She was playing the part of a woman playing a part.