1. You tell him things you don't tell anyone else. We don't mean blurting something out after you've had too much merlot, but the desire to tell him intimate details about your life means you trust him—a major component of successful long-term love.
2. You let her see you in moments of weakness. It's easy to be happy with someone when you're feeling good about life. But what about when you're not doing so well? Do you want to see her when you've been denied a raise, or your cat died or you had a plain old bad day? She should be a comfort during tough times, not a burden.
3. You respect him. You don't want to change the essence of who he is. There may be stuff that irritates you in everyday life—he insists on wearing his favorites, holey T-shirt, he eats sugar cereal for dinner, he still watches Saturday morning cartoons—but you like him, plain and simple.
4. You want him to meet your parents. You feel proud of him and you want to show him off—as opposed to feeling like you have to make excuses for him.
5. You can imagine a future together. You don't have to practice writing your first name with his last name, but do you periodically let your mind wander to picture a life together? Is it amazing?
6. You're not afraid to disagree with him. You know that even if you fight, he'll listen to you and won't brush you off. He takes you seriously, even when he thinks you're wrong.
7. You want to work out your major differences. If you do have crucial differences that will impact your future together—different opinions about religion, money or something else—you want to work them out with him, and you believe you can come to a conclusion that will satisfy both of you.
8. You laugh together. Laughter is one of life's simplest pleasures—you should definitely be able to crack each other up.
9. You're incredibly, utterly, surprisingly attracted to her. Physical chemistry is an undeniably important ingredient in a healthy relationship. And if she's not a classic beauty or your usual "type"? Even more reason to think she's the one.
10. It's OK to be quiet around her. You don't feel like you have to fill the space between you with chatter or other interaction. Instead, you feel an easy comfort.11. You feel like yourself around him. You don't feel like you have to edit your thoughts; you're not self-conscious or anxious.
12. You need him the right amount. You long for him—but not too much. Some neediness is good but too much breeds discontent.
13. You don't feel too jealous. You're comfortable with him going out with his friends—even female friends. You let each other have your own lives and hobbies.
14. You feel like she makes you a better person. She makes you feel smart, funny, attractive, creative—like the best version of yourself. You feel like she brings out and complements the best parts of you.
15. She just gets you. Sometimes it's that easy. You feel like she understands some essential part of you that you can't explain or articulate. It's a warm, comfortable feeling—and one you should have with the person you marry.