J'onn J'onzz

Earth-One / Post-Crisis / New Earth

 * 1)  M'yri'ah  - J'onn J'onzz's wife, the mother of his children, was killed along with the rest of the population of Green Martians, leaving J'onn the sole survivor.
 * 2)  Diane Meade  was an early love interest in J'onn's adventures on Earth. When all the Justice League members took their respective love interests to a carnival, she accompanied him (Justice League of America #7, Nov. 1961).

DC Animated Universe

 * 1)  M'yri'ah  - As in the comics, J'onn's wife, along with his his children were killed along with the rest of the Martian population.
 * 2) Unnamed - After making a resolution to live among humans and try to live a life more connected to society, it is revealed that J'onn has taken up with an elderly woman, using the guise himself of an elderly man. He later talks to her on the phone, saying "I should be home in time for dinner...I love you too."

Arrowverse

 * 1)  M'yri'ah  - As in the comics, this was J'onn's wife and mother of his two daughters. All three were killed in the purge of Mars by the White Martian race.
 * 2)  M'gann M'orzz  - J'onn is elated to find that there is another Martian living on Earth, but horrified and filled with hatred when he realizes she is a White Martian. He is slow to believe that she is one of a number of White Martians who are different from the rest, opposed to the genocide their race committed. He eventually believes her, and the two briefly become something of a couple. Her responsibilities, however, take her back to Mars to find other White Martians like her. The two resume their relationship when she returns, even though it may only be for a brief time.