Russian author Leo Tolstoy opened his novel Anna Karenina with the lines “All happy families resemble one another, each unhappy family is unhappy in its own way.”

If he is right – and I think he is – there ought to be some common ingredients for a happy marriage. So what are they?

1. Decide, don’t slide

Commitment is the foundation stone on which all else rests. It’s the reason most marriages last. And lack of commitment is the reason those that don’t unravel.

When I proposed to my wife Kate, I had decided that I wanted to spend the rest of my life with her. But right up until the moment I asked her and she said yes, we weren’t tied to each other. There was an ambiguity about our relationship; a lingering uncertainty for both of us, no matter how small.

That proposal conversation let us know exactly where we stood. It removed any ambiguity and sent each other a clear signal of our mutual plan for the future.

Of course it’s quite possible to “slide” into marriage, rather than “decide”. But that’s a lot less common today as families and friends pile on the pressure with a: “When are you going to tie the knot?”

So most people head into marriage with a “right, let’s make this work” decision rather than an “oh alright then, let’s see how it works out” slide.

This is why divorce rates are now back to 1970s levels. Today’s newlyweds are deciders.

When you’ve decided to do something, and really bought into it, you’re more likely to stick at it – and enjoy it.

2. Husband, love your wife

This might sound counterintuitive when equality is so important in most things we do. But when couples struggle in their marriage, the way back is invariably in the hands of the husband. More often than not, it’s the man who needs to “decide”, to treat his wife better, to stop behaving badly.

In the same way, when marriages are going well, it’s almost always because the man has taken responsibility for his relationship. He’s committed to his wife, and treats her (and others) well.

This is because “happy wife, happy life” is a real thing. When mum is happy the rest of the family thrives. A number of studies have shown this is less true for dad.

Husband, love your wife. Then she will love you right back. In that order.

The reason, I think, is that women have babies and men don’t.

The experience of pregnancy automatically orients the new mum towards her baby and away from the new dad. So if dad doesn’t take responsibility for the relationship, nobody will. The way couples handle the transition to parenthood sets the trend for years to come.

So husband, love your wife. Then she will love you right back. In that order.

3. Be kind

I don’t think I fully appreciated the importance of kindness until my wife Kate and I started writing our book What Mums Want and Dads Need to Know.

As part of our research, we asked 300 mums how they rated a number of different qualities or attributes in their husband or partner. At the bottom of the list came strong, sexy, adventurous, fixer and provider. That made me laugh. That might be what many men assume would come at the top of the list! It’s not that such attributes are unimportant; they are just not the most important. What mums wanted most of all was a friend, somebody interested in them, and somebody kind.

Kindness is supremely attractive. It’s not just an attitude of mind. It’s something you do.

When somebody is kind to you, it is hard not to respond positively.

When somebody is kind to you, you will want to make your marriage work. Try kindness, and you will find that your wife will want to communicate well, be friends, spend time together and sort out arguments before you go to sleep.

So be kind.

Kindness really is the secret to a happy marriage.

Harry Benson is research director for Marriage Foundation and co-author of What Mums Want and Dads Need to Know

National Marriage Week begins today

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