Just This Once by Evelyn Jeannie Hall

Over a year ago, Lacey and Zane enjoyed a scorching one-nighter. While memorable, that’s all it was ever supposed to be. But a month after that, they wound up having a second go-round. And that time was even hotter than the first.
Now, since they share the same circle of friends and colleagues, they’re forced to interact on the regular. After backsliding into each other’s arms again, they make a fun—yet clandestine—no-strings-attached arrangement.
Once those strings start to tangle, though, things get complicated. When unforeseeable events threaten more than their relationship status, their situation goes from a lighthearted romp to something far more serious, forcing a decision neither of them thought they’d have to make.

Will they choose to face this hard decision together, or will they be permanently ripped apart?