The Conservatives in the UK do. Cameron was saying something a while ago about wanting to give £20 a week to couples who stay married to prevent divorce. As if a tenner's going to stop you. This is the first link I found and is just a coincidence that it's a left wing newspaper

http://www.guardian.co.uk/society/2007/jul/10/drugsandalcohol.money
Conservatives are big on family etc, so marriage is a very important principle to them.