Successful relationships require safety and trust — and a betrayal of that trust can derail a partnership before you know it. That's why cheating can be so devastating to a relationship.

Both in the media and in our personal lives, we tend to associate cheating with physical affairs; however, emotional affairs, even without sex, threaten even healthy relationships just as much.

What is an emotional affair?

Simply put, emotional cheating is an intimate connection with someone other than your partner.

According to Seth Meyers, Psy.D., writing in Psychology Today, "Emotional infidelity refers to the behavior that one partner engages in which fosters emotional intimacy in the here-and-now with someone else, and sometimes promotes the possibility of sexual intimacy in the future."

More to the point, it's when that person becomes central in your life and, in some important ways, takes on the functions of your partner. You find that you spend a lot of time with them, confide in them and support each other emotionally, whether it's over the phone or in person.

The emotional investment draws energy and commitment away from your relationship, resulting in you growing distant from and less interested in your partner. You may even begin to regard the other person more favorably than your partner, so you become increasingly annoyed or frustrated with your partner's perceived "limitations."

Even if the other person is someone you aren't physically attracted to and there's no risk of physical intimacy between you, it's still a threat to your relationship and it still can (and should be) considered an act of infidelity.

How do you know if you're having an emotional affair?

The following are 5 concerning warning signs of emotional cheating to watch for:

1. You confide in this person.

You tell them intimate things about your life that only your partner knows.

2. You tell them about personal aspects of your relationship with your partner.

Perhaps you tell them about the physical and/or emotional problems you're facing.

3. The thought of introducing your partner to this person makes you uncomfortable.

You don't want to spend time with this person while your partner is around — you want to keep this relationship to yourself.

4. You find yourself not being fully honest with your partner.

You find yourself hiding from your partner (or others) how often you see this person or what you share with them.

5. You think about the other person a lot.

You're excited to see them and talk to them, more than with even your closest friends.

What can you do about it?

A healthy relationship means that your partner is your first priority, you've built your relationship on trust and honesty, and your partner is your "go-to" person for most things.

If this isn't happening, then it's time to make a change and confront the issues directly.

When it comes to recovering from emotional cheating, most couples need the help of a professional couples counselor.

Though hard to imagine at first, especially after an emotional affair is first revealed, many couples not only recover but actually improve their relationship as a result.

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Gal Szekely, MFT, is a marriage and couples therapist, as well as a Founder of The Couples Center, with therapists in San Francisco, Berkeley and Palo Alto who specialize in helping couples navigate challenges and rebuild relationships.