Saying “I love you” seems simple. If you love someone, you tell them. But, for various reasons, people don’t always express how they feel. They are afraid or they just get distracted by day-to-day life and forget to say how they feel. Whatever the reason, saying, “I love you” is important to do for many reasons.

Love Is Contagious

Neuroscience research shows that the more you focus on your love, gratitude and appreciation for others, the more they will feel those same emotions, writes psychologist Daniel Jay Sonkin on MentalHelp.net. Telling him that you're really thankful that you have him in your life will help him to feel more thankful for you, as well.

It Makes You More Empathic

Expressing love can make you more positive and empathic, strengthening your connection with your partner. It can also decrease activation of fear centers in your brain, reports psychologist Melanie Greenberg in “Ten Science-Based Facts About Love” in Psychology Today. Telling her that you love her helps you to maintain a positive attitude.

It Makes You More Loving

We don't have a fixed amount of love. In fact, writes Greenberg, when you focus on your loving feelings for one person, it can make you feel more loving toward others. Examining your feelings for him can help you to realize how much you also love your friends and family.

Love Is an Emotional Connection

Telling her that you love her shows that you understand the difference between an emotional connection and physical attraction, writes Greenberg. This is an important distinction for you and your partner to make. An emotional connection is the basis for a relationship; physical attraction is not.

It Makes You More Trusting

According to Greenberg, expressing love can also help you and your partner to feel more secure and trusting in your relationship. Telling him that you love him can lead to more open communication, sharing of thoughts and emotions, and more positive feelings toward each other overall.

It Can Show Appreciation

Telling her that you love her shows appreciation and, according to Greenberg, this can increase satisfaction with the relationship. When one person feels taken for granted, they can more easily become unhappy in a relationship. Being appreciated can decrease your partner’s desire to find satisfaction elsewhere.

It Can Lower Your Stress

People in committed relationships tend to show lower stress levels, reports Greenberg. Telling him that you love him may enable him to experience difficult situations with less stress and to rebound from those situations faster and more easily.

It Can Help You Live Longer

Deepening a connection through the expression of love can improve physical health. Greenberg reports that marriage, especially for men, increases the life span significantly. Women, too, are helped by relationships, and show decreased levels of heart disease and also increased life spans. Expressing your love for her may not only help her live longer, but may help you live longer, as well.

Love Is an Action

Love is an action. If you don’t express it, it becomes unimportant and false, states Rabbi Shmuley, on Oprah.com. A lack of expression can lead to the assumption that love is no longer present in the relationship. Don't assume that he knows that you love him -- make sure that you tell him -- and that you also show him.

Love Can Renew a Relationship

Expressions of love can help to reconnect if you’ve been in a relationship that has lost some of its spark. Taking the time to focus on one another may be exactly what your waning relationship needs to bring it back to life, advises Sonkin. Take some time and focus on her. Make sure to tell her that you love her. Give her the time and attention she deserves. Your relationship will be the better for it.