Hellfire by Vi Summers

Every soldier has their own way of escaping their demons: men are my outlet. They’re nothing but toys, with the exception of Avery Montgomery.
It’s him I reach for when a mission goes horribly wrong. He catches me as I spiral, then vows to never let me go again. But as new revelations unfold, another mission takes me abroad, and this time it’s personal.
A web of deception lies in wait. One that’s thirty-five years in the making and designed to imprison me within a corrupted legacy forever.
With time running out, all I can do is pray that Avery and the Phoenix Force team find me before my fate is sealed.