His Manny Omega by Harper B. Cole

Wyatt’s has no interest in confusing his daughter by bringing a female nanny into their house.
The three years since his wife Jen’s death, their neighbor has been more than willing to take on the role as Chloe’s nanny. But she’s ready to move near her own grandchildren, and Wyatt has to find a replacement. The requirements are that they be willing to live in his home, love children, and be male.
Oliver has found fulfillment taking care of other people’s children since he can’t have his own.

After his alpha broke up with him because he couldn’t have children, Oliver found a job at the Omega House, running their childcare program. He finds the job fulfilling, but it’s not easy, keeping up his optimism in the constant evidence of the result of evil.
It seems like a perfect match.
Oliver is certain he can keep his attraction for his straight boss under control, but he can’t help the way Wyatt and Chloe have captured his heart. Wyatt has never been with anyone but his wife, but it’s becoming harder to deny that his thoughts toward Oliver are straying into decidedly dangerous territory.
As for Chloe? She has only one wish: for Oliver to become her daddy.