Simply Irresistible by Marlie May

A secret baby.
A marriage of convenience.
Six years of lies unraveling.
(A best friends-to-lovers, second chance romance)
When Cara moves home to Maine, she plans to open a tea shop, raise her four-year-old daughter, and keep the promise she made after losing her husband: no romance. Sure, she’ll run into her former best friend–and one-time lover, Roan–but she’s no longer the silly girl who flung herself at him that night after college graduation, only to be told the next morning it was a big mistake.
Roan has a hard time trusting anyone since his now ex-wife embezzled from him. So, when Cara, the woman who stole his heart in college, moves back to Crescent Cove, he’s determined to keep things platonic. He ruined their friendship when he made a play for her six years ago, and he won’t make the same mistake again.
But Cara’s in-laws sue for custody of her daughter. To help Cara win the case, Roan offers a marriage of convenience. Close quarters during their tropical paradise honeymoon in Costa Rica ignites the heat they once shared, making it hard to remain just friends.
Will Cara remain true to her vow to her deceased husband or will she take a second chance on love.