Besides the potential thyroid issue, what is going on emotionally/romantically between you? You need intimacy and good couple energy to feel sexy. Or, I mean most women do. Do you get out on dates? Is your son ready to spend a weekend with a trusted friend or family member?
It can be hard to switch from mama to sex kitten on a dime. One needs to make that transition.
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve.
~Percy Byshe Shelley