Death and Divination by Debra Dunbar

Ophelia Perkins faces death’s reapers every day—she never thought she’d fall in love with one of them.
As an oracle, Ophelia divines the future—and sometimes there is no future for the people she fights to keep alive in her job as a paramedic. Those countless lives she’s saved never seem to outweigh the devastation of losing a patient.
One night, one patient she can’t bear to lose, and Ophelia makes a deal with a reaper—save this life, and in return she’ll trade him her own. With the deal struck, Ophelia walks each day with a reaper by her side and waits for the scythe to fall, only to find out this reaper is more than just an agent of death, he’s the man she wants as he happily ever after.