There are several things you should see during a hug when true love and affection are felt (see also Body Language Secret # 105: Parental Love and Affection). One of these is a touching of the heads and necks accompanied by a bending of the necks. It's as if you're trying to get the maximum surface area possible in contact with the other person. This is true between parent and a child as well in romantic adult relationships. The persistent absence of this highly characteristic Body Language signal is particularly worrisome.