He met his wife, Jessica, online 17 years ago, got married in 2004 and have three children together.
But in a Facebook post on Friday, 17 July, Turner announced: After much thought, prayer, and counselling, Jessica and I have made the decision to end our marriage.
While were best friends and thoroughly love doing life, parenting, and pursuing our dreams together, ending our marriage is necessary because I am gay.
The Christian author explained that being gay was not a new discovery for him, and added: As someone who spent 30+ years in fundamentalist/evangelical churches, exploring God through conservative theologies, Ive lived many days overwhelmed by fear, shame, and self-hatred.
Though my own faith evolved long ago to become LGBT+ affirming, my journey toward recognising, accepting and embracing myself took much longer.
But for the first time in my life, despite the sadness and grief Im feeling right now, I can say with confidence that Im ready to embrace freedom, hope, and God as a gay man.
He added that his wife had loved and encouraged him to be himself.
Jessica also posted on social media addressing her separation from Turner, writing: My husband, my best friend has bravely shared his deepest truth this past year. He is gay.
While this doesnt change how much we love him, it does change our relationship. We are moving forward with ending our marriage, while remaining deeply committed to our family and each other.
