Falling for the Forward by Brenda Rothert

Suki Brennan is broke. After she co-signed several hefty loans for her ex’s business, he fled the country and left her working two jobs to pay his bills.
So when her new boss, a sulky pro hockey player who recently became the guardian of his three nieces, proposes a deal to help him secure permanent custody of the girls, she agrees.
If Suki fake marries Carter Stanton for one year, and pretends to be his doting wife, she’ll get half a million dollars and a clean divorce at the end. Not only will the money pay off all her debts, she’ll be able to help the girls she already adores settle fully into their new lives.
It’s a foolproof plan. At least, it seems like it. As Suki grows closer to Carter and his nieces, though, her feelings for them become very real. But does her brooding boss feel the same?