While Matt Murdock never went so far as to take a life, he did throw himself even deeper into his vigilante life, so much so that he ruined his personal life.
Daredevil was put through the ringer in Season 2, and not just physically by battling bad guys for days on end with multiple injuries and little sleep.
His focus on Elektra and The Hand also ruined his romantic relationship with Karen Page.
Nelson & Murdock collapsed, not only leaving him without a job, but his friendship with Foggy damaged.