Men, you have the power to make or break a relationship. My research has consistently shown that what men do in a relationship is, by a large margin, the crucial factor that separates a great relationship from a failed one.

This is why my wife Julie and I wrote The Man’s Guide to Women.

We want to share this knowledge with you. In short, the secrets from the Love Lab are the secrets that every man needs to know. 

If you’re ready to understand what it is women want and need, how to best provide it, and what it takes to be in a happy, loving relationship with a woman for a lifetime, let’s start with the four things you never say to a woman.

1. “What is it now?”

This conveys impatience and anger about what is probably her bid for connecting with you. Every attempt she makes to connect with you is an opportunity to turn toward her needs and connect emotionally. This is foreplay. Don’t blow it.

What to say instead: “What’s on your mind, baby? I’m listening.”

2. “You used to have a nice body. I really miss that.”

Instead of being a compliment, this is an insult. If you want to talk about her body, first realize that she is already looking at 600 visual ads a day that shows her our culture’s ideal female body. Research has revealed that even very fit, good-looking women tend to feel bad about their bodies.

So, find something you genuinely love about her body, or how gracefully she moves, and pay her a sincere compliment. Men who sincerely compliment their women every day have better sex lives than men who do not.   

What to say instead: “You look gorgeous in that dress. I love that color on you.”

3. “Fine, have it your way. You always will.”

This turns her need into a power play and a win-lose, zero-sum game. You are suggesting that by having it her way, her intent is to win. It also avoids looking for the need she may have in a request she is making of you.

What to say instead: There are two magic questions to ask a woman: “What do you feel?” and “What do you need?”

4. “Why do you always have to be so needy?”

First, this is clearly an insult. It turns a need into an insulting personality trait and it’s probably not even true. We are all needy. Relationships are contracts of mutual nurturance, so having needs and agreeing to meet those needs is an implicit hidden contract in any love relationship. Second, it converts a potential opportunity — turning toward her need for you — into a statement of turning against her.

What to say instead: Again, remember that there are two magic questions to ask a woman: “What do you feel?” and “What do you need?”