'Golden Bachelor' Gerry Turner Had Suicidal Thoughts After Theresa Nist Divorce

Gerry Turner is opening up about the brutal public backlash after his split with Theresa Nist ... admitting the 'Golden Bachelor' heartbreak hit him so hard, he spiraled into suicidal thoughts.

TMZ has obtained an excerpt of Gerry's upcoming memoir, "Golden Years" ... and he writes that after announcing his divorce just 3 months in last year, the negative reaction got so brutal he hit rock bottom ... writing, "One night, while I was lying in bed and staring at the ceiling, it all became too much, and for the briefest moment, I thought about putting a gun to my head."

In the excerpt, Gerry explains he’s always had a "marathon mentality" -- pushing through pain knowing it would pass. But he admitted that at the time, the agony felt endless.

Gerry says the dark thoughts vanished just as quickly ... because he immediately pictured his daughters, Jenny and Angie, and knew he could never put them through that. He clarifies the moment wasn’t about wanting to die ... but more about wishing he could just disappear.

And that’s exactly what he says he craved as soon as the public scrutiny started piling on ... writing, "I dreamed of renting a room in some remote part of Alaska no one had ever heard of and not coming out for a month" -- a shock for him, since "he had never been the depressed type.”

Gerry also gets candid about the behind-the-scenes fallout with Theresa ... saying they had a pact to shield each other from bogus headlines, but he says she broke the deal by putting out her own statement just days later.

Still, he’s promising the full ride -- from reality TV fame to heartbreak, and the lessons he’s pulled from it all -- in his memoir "Golden Years," hitting shelves Nov. 4.