Good news! The couple who drink together stay together. All those nights sitting at the kitchen table glugging pinot noir might be bad for your liver but they are good for your relationship. Well, sort of. What the University of Michigan's survey actually found is that couples with similar drinking habits are happier than those in which one person is lining up his third G&T while the other is nursing a fizzy water and a grudge.So long as you are in sync you are effectively working at the relationship. You could be doing couples' yoga, or walking, or tantric sex, or, alternatively, you could be getting quietly sloshed - because that's also a bonding activity.It is all about similar personality types. But it is also a reminder of the many ways in which drink can be essential to a marriage.For a start it's the crucial gear-changer, the signal that you have to switch off the iPad and properly engage with the partner you basically never see.With a drink you're automatically in the zone. It's code for: "Let's switch off Boring Knackered Us and bring out Old-Style Us! Or just Slightly More Fun Us!"There are many options. You can get serious over a drink: it gives you licence to say things like: "No, but honestly, do you want to hear what I would do if I were Barack Obama?" And you can get seriously silly over a drink.You can ask important questions, you can be honest, or rude, or provocative . and that's not only allowed, it's expected.Without a drink you are on normal time with normal rules. Stone-cold sober you are going to catch up on each other's day, the top-line domestic news, load the dishwasher beautifully and be tucked up in front of the TV before you can say: "Um, maybe I will have just the one."Ever marvelled at how you still have a tankful of chat to share with your loved one at 1.30am on the last day of your holiday? That would be the rosé.Think back to when you last danced, had sex, laughed until the children asked if you could please shut up - guaranteed it was drink that stopped you from getting an early night.There will be times when drink is not your friend in marriage. There is always one who will take free and frank discussions too far.There are those moments when you suddenly find fault with your beloved. (One minute you're watching them opening the fridge, and then when they innocently ask: "Don't suppose we have any cheese?", that's it! You are stomping up the stairs, huffing and puffing.)Hangovers are not particularly good for relationships, especially the nervy sort when you begin to question every choice you have made in life and then get an overwhelming urge to look for your lost earrings.But, on the whole, handled with care, alcohol can be marvellous marriage petrol. Just as discussion-provoking, dis-inhibiting, laugh-inducing and liable to make you fall in love as it ever was. Cheers! - ©The Daily Telegraph..