Sylvie and Antonio’s relationship had one huge problem — it was bumpy. Very bumpy. It got to the point where their makeups and breakups were so frequent that fans likely needed a scorecard to keep up with them.
Back in Season 5, Antonio first turned Sylvie down when she asked him out because he was still dealing with messy emotions connected to his breakup with his ex. They went out anyway, then broke up after a confrontation between Sylvie and the ex. But Antonio and Sylvie ended the season by making out in his squad car, which led to the 6th season where they hooked up repeatedly. This resulted in a pregnancy scare for Sylvie, and just as she had gathered up the courage to tell Antonio she wanted a more serious relationship with him, he told her he was about to go out with another woman.
Since Antonio’s actor, Jon Seda, left the show during the 6th season of Chicago Fire, and Sylvie has since started tangling up with Matt Casey in a pairing that has divided the show’s audience, it appears that the twosome’s breaking-up days are long gone. But one never knows when it comes to the One Chicago universe.