Men often complain that they don't know what women want – it was even the subject of a Mel Gibson movie of the same name.
But now a Baptist minister has come up with an app which he says makes men's lives easier.
For for the past three years, Mark Reilly, 45, has been the senior pastor at Camden, where he lives with wife of 18 years, Donna, and their two daughters, aged 13 and 10.
He said his Legend Husband app gives men an idea of what their wives really need from marriage.
Mr Reilly said he used his many years of experience leading couples through pre-wedding and marriage counselling, as well as marriage enrichment seminars, when designing the app.
He said the Legend Husband app grew from a discussion at a party.
"I joked I needed a wife app, then we discovered that none of the men in the group knew their wife's shoe or clothing size, much to their wives' horror," Mr Reilly said.
He said he was able to put to use "all the stuff I've done wrong over the past 18 years of marriage" when designing the app, which includes a place to record important dates such as birthdays and anniversaries, favourite flowers, and a place to jot down dress, shoes, ring and bra sizes.
Users can also note specifics such as the locations of first dates, wedding songs, and joint goals.
And for when things aren’t so rosy, there’s even an argument “referee” – a feature that changes the screen’s colour when it's your turn to talk.
"While the screen is pink, it's her turn; while it's blue, it's his. Everyone gets to say their piece uninterrupted, without having to shout over their partner," Mr Reilly said.
There's also a video feature so you can record each other saying how much you love the other person, which you can then play back “when things are crazy".
And what does his wife think of the app?
"She loves it - she's very supportive of it," he said.
He admitted that a Legend Dad app might be in the pipeline, but said he lacked the knowledge to write a Legend Wife app.
You can buy the Legend Husband app from iTunes for 99c.
Mark’s tips to keeping your partner happy
- Try to meet your partner’s needs, but bear in mind that ‘‘no one person can meet everybody’s needs’’.
- Show your wife you love her, don’t just tell her. Mark suggested surprising her with a small gift - he says he might buy his wife a Cherry Ripe ‘‘just to let her know that I am thinking of her’’.
- Have regular date nights. Mark and his wife pencil theirs in every week, but it might not happen for a fortnight - but money or lack of a babysitter shouldn’t matter. ‘‘It can be maybe going out, even for a coffee,’’ Mark said. ‘‘You can cook a nice dinner at home. Or you can tell your [older] kids ‘this is our time now’ and you go to one half of the house, or go to the bedroom and lock the door.’’