You could be in a marriage for which people believe you are happy since they are seeing you with a companion, yet they don’t know how sad and lonely you are. It is very common that most people nowadays are both married and lonely. Loneliness in marriage develops slowly- almost unnoticeable, and discrepancies are only discovered after many years have passed.
If you are married but lonely, chances are that, your partner is lonely as well. Both of you are trapped in an emotional disconnection and you have no correct method of breaking it. To avoid falling into such situation, take the initiative and talk to your partner about the issue. Listen to their views empathetically, and try to view things in their perspectives.
Allow enough time for your partner to reciprocate. After talking to your partner in the most polite way and have pointed out the problem, never expect immediate changes. Remember, habits are difficult to change. Give them enough time, and keep encouraging them. Also, you can get rid of loneliness by revitalizing your sweet memories. Talk to your partner about the sweet moment you ever shared together and if possible, visit the beautiful places you ever visited together. You can also spice your marriage by suggesting less complex activities that you can do together. For example, making a video call with old friends, writing a letter to a family member, and cooking a meal together.