This year, we interviewed dozens of relationship therapists and researchers on which phrases successful couples say to each other. Most experts agree that couples who thrive consistently express empathy, boundaries, and a desire to find common ground.

There are some phrases, though, that even those in healthy partnerships don't say. That's because they are less intuitive or feel more selfish than "I appreciate you" or "Help me understand this."

Even our most uncomfortable emotions need to be voiced, says Lisa Marie Bobby, psychologist and founder of Growing Self Counseling & Coaching in Denver.

"Clear, respectful communication feels good for everyone," she says.

Here are four phrases people don't say enough to their partners.

1. "I have a request."

"If you say it nicely it puts your partner on notice that you're about to say something serious, important, and actionable," Bobby says.

Tell them why you are making this request, ask for their input, and then close by asking if there is anything they need from you.

Altogether it should sound like this: "I have a request. The next time you load the dishwasher can you turn it on? That way it will be clean so I can unload it in the morning. Would that be alright? Amazing. Is there anything you need from me?"

2. "The story I'm telling myself ... "

Checking in with your partner about how recent events made you feel is healthy. But, talks like this rarely go well if one or both of you feels attacked, says Dené Logan, a therapist and author of the book "Sovereign Love."

Starting a conversation with "The story I'm telling myself" might help mitigate some of that defensiveness.

"When we say, 'The story I'm telling myself is that nothing I do is ever good enough for you' instead of simply saying, 'Nothing I do is ever good enough for you,' it becomes a way of taking ownership of our thoughts and leaving space for misinterpretation," she says.

3. "Will you tell me more about what that brought up for you?"

It's easy to assume our partner always knows what we are feeling or why. But, no matter how long someone is in your life, it's impossible for them to understand where you're coming from 100 percent of the time.

This phrase can "bring our partner in on the historical context of our pain points," Logan says.

"If, for instance, I felt criticized by my partner in a way that reminds me of being criticized as a child, my partner asking to hear more about that historical context can be an incredibly reparative way to build deeper intimacy between us," she says.

4. "Let's do a year in review."

Take account of moments you'll cherish, conflicts you navigated and personal accomplishments, says Thema Bryant, a professor of psychology at Pepperdine University and former president of the American Psychological Association.

To help direct the conversation, Bryant recommends following up with a few questions:

• What is a moment this year that you're glad we survived or overcame? 
• How did I help you bloom or grow this year? 
• Is there anything I did or said this year that was hurtful to you that we have not discussed?
• What are you looking forward to for us next year? 

The end of the calendar year is a natural time to do this, but you can do a review at any time.

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