In a lot of struggling relationships, every touch has become a question. Once a hand on a back reliably means "are we?", people stop reaching out, and the distance grows from there.
Protect touch that means nothing
A hand while walking, a shoulder in passing, sitting close. Touch with no agenda is what stops physical contact becoming a negotiation.
It is not a lesser thing
For plenty of people this is the main event and sex is one expression of it. Treating affection as a preliminary misreads half the population.
Notice who has stopped
Withdrawal of casual touch usually happens long before anyone says anything is wrong. It is the earliest signal most couples get, and the most ignored.
Rebuild here first
Couples reconnecting after a rough patch almost always do it through ordinary touch long before anything else.