Twenty-Four Days by Janet Albert

Sometimes life forces us into uncharted territory, as Dr. Miranda Ross discovers when circumstances lead her to seek employment on a cruise line specializing in all lesbian cruises. Although she's single and surrounded by women, she has little time to socialize and even less inclination. She's made promises to herself, promises she intends to keep. And keep them she does, until she meets the ship's head fitness trainer, Jamie Jeffries. Jamie has the kind of body and good looks most people only dream of and unfortunately, a reputation to match. The buzz on the ship is that she can have anyone she wants and often does. Miranda fights valiantly to avoid Jamie and the unwanted attraction that seems to have a will of its own. She's strong and determined...but a lot can happen in twenty-four days.