If there was any PR couple that really lasted long, it was Lord Zedd and Rita. So okay Lord Zedd didn't like Rita when he first appeared on the show because she failed to capture the Earth and banished her away. But he underestimated her that she was able to return to the moon, drugged him with a love potion and ended up marrying her while she planned to take over. But things went rather differently after their rather funny wedding which led to one of the most dangerous alliances in history.
So what happened next? Rita came to truly love Lord Zedd for who he was and not for his power even if he was still under the influence of the love potion. Lord Zedd on the other hand was coming to accept Rita as his wife. The two had rather difficult journeys while designing even deadlier schemes as a couple. Even when Lord Zedd had toned down in terms of his temper, it didn't make him any less dangerous.
So Goldar discovered it was all a sham and tried to administer the antidote but to everybody's surprise, Lord Zedd was still in love with Rita. Theoretically saying, Lord Zedd may have suppressed his feelings for her long enough that even when the antidote was administered, it was no use or that nobody was aware of the potion's fading effects while Lord Zedd's love for her began to surface on its own. Of course while Lord Zedd became less scary, he wasn't getting any safer now that he and his wife came up with better plans, many times nearly spelling the end of the rangers. Their only problem lies on the fact that Rito her brother had become a numbskull even if he helped them destroy the Thunderzords.
So it came to a point that they planned to torture Kimberly Hart by draining her life force away to force the rangers to pilot the Shogunzords. Very wicked move. However their ally Catherine turned against them and replaced Kimberly Hart who fortunately survived. So they did end up destroying the power coins then the Command Center only to discover they had to face the Machine Empire. They did succeed against the Machine Empire but they were still left wandering, no longer finding a place to stay home for some reason. Eventually by Power Rangers in Space, they were turned into human form.
Later, within the TV canon, Rita Repulsa became Mystic Mother although the Sentai counterpart, Rita and Mystic Mother were not the same person. We don't know of what happened to Lord Zedd although their evil son Thrax showed up. When Thrax was born is left out of the question.