Thou Shall Knot by Briton Frost

Conner used to have an easy life. Like most alphas, he worked hard—but played harder. Until his days of playing came to an abrupt end after an accident took his sister and made Conner guardian to his two toddler nieces. He knows absolutely nothing about raising kids or taking care of a family. The only thing he does know is that he’ll do whatever it takes to give the babies the love they deserve. Luckily, the babysitter next door steps in to help.
Damon is an omega with a strong nurturing instinct, and he makes taking care of the house and the kids look easy. But Damon is young, too young. And handsome, way too handsome. Playing house with the boy-next-door is a bad idea for everyone and makes Conner feel like a dirty, dirty cliché. He knows Damon has a crush on him, and he should do anything in the world but act on it.