Breaking Orbit: Volume I of the Titan Run Trilogy

Life is what happens when you're busy making dinner plans.
Hugh Saracen thinks he has it all: A fulfilling career, a loving husband, and PTSD after losing his lab partner in a field accident on the surface of Mars. When Hugh's husband Dalton receives a promotion, the cracks in that perfect life become impossible to ignore.
On the far side of the red planet, Ann Bell lives a life deferred as she cares for her dying mother. A moment of compassion from Ann forces her to abandon everything she's ever known to preserve her freedom.

Two people with nothing in common beyond the world they both call home. Two people with their own agendas. Two people leaving everything behind to do the deadliest job in the Solar System: The Titan Run.