I'm incapable of making a healthy couple unless I simply neglect to develop them. These two have a good mix of communication issues, separation anxiety, codependency, and paranoia. But in my defence, they're a Gotham couple, and most of their issues are because of being in Gotham.

"All you have to do is stay a minute
Just take your time
The clock is ticking, so stay
All you have to do is wait a second
Your hands on mine
The clock is ticking, so stay"
https://www.youtube.com/watch?v=h--P8HzYZ74

Context:
Tim was very independent, terrified of feeling chained down or trapped, spending most of his time out in the city streets where he didn't feel confined by walls, or otherwise going wherever he wanted whenever he wanted. Bernard was the opposite, feeling like anywhere could be dangerous, every shadow could be hiding some unseen danger, even in familiar places. The only way he felt safe was with Tim by his side, knowing he'd protect him. Tim was always aware of his surroundings, always knew who could be trusted and who was a threat, and knew every possible danger Gotham could throw at them. However, Tim would often leave for long periods of time without a word, leaving Bernard feeling vulnerable and afraid, often spiraling into panic attacks. He tried to get Tim to stick around more often, or at the very least give some idea of where he was going or how long he'd be away, but failed to make it clear just how important it was to him, not wanting to push Tim to feel restricted.