Oh yes there is. If his wife finds out, there'll be hell to pay!There's nothing for Bill to be scared of
Getting cold feet is definitely more generalised than just a wedding. One can get cold feet on a business deal where suddenly you realise the risk you are about to take going ahead with the merger: you get cold feet and blackout of the deal.I wouldn't say getting cold feet has anything directly to do with being scared. It's simply a matter of having doubts or "second thoughts" which steer one towards changing one's mind.
Of course the doubts may in turn be caused by fear, but they need not be. As you say, lack of enthusiasm can suffice. Nevertheless I'm not sure "cold feet" is much used at all outside of its most usual context, which is not going ahead with a wedding.
Oh yes there is. If his wife finds out, there'll be hell to pay!