Yes, I have to go with a couple who faced a lot of adversity, not least the fact that Jim started off in a near-toxic relationship with Barbara, which more or less ended because Barbara realised she was gay/bisexual, and cheated on him with Tabitha.
The first obstacle came in Season 3 when, after disappearing for the final six episodes of Season 2, she was suddenly in love with Don Falcone's son, and things just went downhill between them, mostly because: 1) Jim had to choose between having Jervis Tetch (I think) shoot Lee or his current crush; he chose Lee. 2) Lee's husband was infected with the same virus that turned Barnes into a psycho; Jim had to shoot him as he was about to kill Lee; because of him being behind her, she didn't realise, so that started a bad patch between them that seemed to last until the end of Season 4, when she went into a Bonnie and Clyde like partnership with The Riddler.
The only fault I have with what happened between them in Season 5 was that, because of the truncated season, it was a tad rushed.
Lee returned, a big surprise, in episode 5x06, after I'd assumed the Riddler succeeded in killing her in the Season 4 finale, but she almost killed Jim because she had been turned into a sleeper agent.
Then, at the end of episode 5x09, they were suddenly getting married - it was a tad weird, though the episode itself didn't deserve to be slammed quite as much as it was on the worst episode lists.
Day 22 - Favorite series finale Day 23 - Most annoying character Day 24 - Best quote Day 25 - A show you plan on watching (old or new) Day 26 - OMG WTF? Season finale Day 27 - Best pilot episode Day 28 - First t.v show obsession Day 29 - Current t.v show obsession Day 30 - Saddest character death