Thou Art The Man by Mary Elizabeth Braddon (1835 - 1915)

Sibyl married after assuming that her cousin, with whom she was in love, died. However, said cousin, who suffers from epilepsy, found himself near a murder scene and had no idea what happened. Fearing the worst, he ran away. Ten years later, Sibyl discovers that he is alive. What happened on that terrible night? - Summary by Stav Nisser