Have the same philosophical/moral sensibilities—The way you look at life, how you raise your children, common goals, etc., are the foundation. You can be different ages, ethnicities and backgrounds but the sensibilities must be in common. Like building a house, it’s the foundation that anchors the house and weathers the heat and the rain. The art, furniture and design are all wonderful, but those are perpetually changing factors; it’s the foundation that’s sustains.
Choose your best friend. This cannot be overemphasized. Chemistry is wonderful, and should be the initiating factor, but it’s the person you want to stay on the phone with all night that you want long-term.
Pick someone who has the same issue as you, and the conversation sounds like this: “We’re going to run out of money,” one says. “I know we’re going to starve,” the other replies. Try to pick someone who doesn’t have the same issue as you, so the conversation sounds like this: “We’re going to run out of money,” one says. “We’re going to be OK; we’ll figure it out.”