Old Sins, Long Shadows (Children of Night Book 2) / PG Forte,

Of all the mistakes Conrad Quintano has made, driving Damian away is the one that haunts him the most. He hates the fact that’s he’s hurt the man he loves more than anything. For the sake of the twins, though, Conrad and Damian parent as a united front, a challenge that grows more and more difficult with each passing year. And with Conrad in his weakened state after his kidnapping, it grows more difficult than ever to be around the one man he can’t have.

But an old enemy’s mission to create a dangerous new breed of vampire threatens the twins’ lives, and it’s now more important than ever that the estranged lovers put the past behind them, or everything they hold dear might be ripped apart.

Each story in the Children of Night series is a standalone story and can be enjoyed in any order.
Series Order:
Book #1: In the Dark
Book #2: Old Sins, Long Shadows
Book #3: Now Comes the Night
Book #4: Ashes of the Day
Book #5: Fallen Embers
Book #6: To Curse the Darkness