If there was one thing Martin had learnt in time, it was that Douglas' opinion of himself wasn't nearly as high as he liked to boast about. After three failed marriages the man's belief in his own 'terrificness' had quite dwindled, even more so since Helena had left him for someone younger and supposedly more attractive.
Now that they lived together it was a fairly common occurrence for Martin to catch his partner staring at his own reflection with something in between disapproval and resignation; Douglas was approaching sixty, that was true, but it didn't mean he couldn't charm the pants off anybody if he ever set his mind to it.
It was when Douglas started making half-hearted jokes about their age difference that Martin decided he'd had enough of this.
"Stop it," he snapped after a particularly stressful day at work. "We're still within the age disparity deemed acceptable according to the 'half-your-age-plus-seven' rule. And while I do think you're terrific, that's not the reason why I'm happy to be with you."
The first officer raised his eyebrow in mild amusement. "The – what – rule?"
"It's just a thing I've found on the internet. 'Never date anyone under half your age plus seven', that's about the size of it. And given the fact that I'm thirty-six, that still gives you a margin of about six months."
Martin couldn't help but scowl at the roar of laughter that followed, though he was secretly relieved to have the old Douglas back.
"Of course you would look up the rules and regulations, even when it comes to relationships."
"What of it?" he shrugged defensively, only to relax into his partner's embrace.
Neither of them was perfect, but it didn't matter in the slightest. All that mattered was that they cared for each other.