Chance Encounter by Tess St. John

While attending a masked ball, Miss Jean Green rushes into the dark study to share a kiss with her intended. As soon as their lips touch, she realizes she’s kissing the wrong man. She should break the kiss, yet she is so intrigued she deepens it instead.
Just having arrived in London to escort his sister for the Season, Mr. Liam Jacobson expects the events to be tediously boring. He has a change of heart when he’s suddenly being kissed by an angel. The woman is perfection in his arms.

That perfection is short-lived, however.

CHANCE ENCOUNTER is Book 4 in the Chances Are Series. Each book stands alone, but might be more enjoyable read in sequence.