Set Season 2, Episode 1. Ianto’s had his heart broken four times. And maybe that’s a good thing.
Hearts That Break
He’d thought when he’d lost Lisa that his heart had broken for good. That it would never happen again.
Then she’d tried to convert him, and Myfanwy had finished her off, and his heart had broken again.
When Jack had taken him to bed for the first time, after the cannibals, he’d felt something besides pain for the first time since Canary Wharf, and realized a heart mending itself could hurt just as much as the breaking.
The hurt continued through Suzie’s resurrection and second death, through Tosh’s heart breaking over Mary, and solving Eugene’s murder, and Jack breaking his own heart a bit over the first Captain Jack Harkness.
Then Jack died, for what they thought was the final time, and his heart broke for the third time. Like the Americans said, three strikes and you’re out.
Then Jack was alive again, and he had just enough time to think that maybe the phrase The third time’s the charm was truer to his situation, before Jack hitched a ride on the outside of the TARDIS.
With the fourth breaking of his heart, once again the second time for the same person, Ianto Jones thought that maybe the pain of being broken wasn’t so bad, as long as he never had to mend the breaks again.
When Jack came back, for what he promised was the last time - “I’ll never leave you again, Yan,” he whispered into Ianto’s hair as they held each other all that night, exchanging kisses and caresses after their very first actual date. “I promise, cariad.” - Ianto finally realized that it didn’t matter how many times a heart broke; all that mattered was that the love used to put it back together was strong enough to hold.
A broken heart that loved and was loved, could be even stronger than a lonely whole one.