I didn't read the whole thread because he topic is just a little painful for me. However, this is pretty much exactly what my dad did. I'll give youa sneak peak on how this kind of thing can often play out.
My parents married in 1973 and had three kids over the next 10 years, I'm the middle child. In 1973, being from a tiny town in rural Northern California, there were no known gay people, but my dad knew he was different, he even told my mom on their way to their first Air Force duty station. She told him it was a phase or something and they went about their lives until 1985 or so, when my dad told her again, she left for a time but my dad hated being away from his family so he promised to "get help" and fix himself, so they could live happily ever after. Fast forward a couple years and we move to a country in Central America, where he meets a man, he starts a 3 year long affair. We move back to the states and about a year later my dad comes out to me and my older sibling and leaves. He then decides he wants to be free from responsibility and pretty much completely abandons us for the next 15 years. Only when his free, partying lifestyle made him terminally ill did he come back into our lives in a meaningful way.
He was around on and off, but we always took a back seat to his social life. We lived in the same town for quite awhile and would only see him once or twice a year. He didn't come to my wedding or even remember I got married. He wasn't there in any way, refused to pay child support, refused to "babysit" us for a weekend so my mom could have a break. So many years of pretending made him a completely different, selfish person, when he was not longer able to keep up the pretense.
I beleive his abandonment had a lot to do with guilt, and he covered his guilt with sex and drugs. He still apologizes regularly even though we've all forgiven him. My parents actually live together again and my mom takes care of him because he's very unwell. They had an amazing marriage for 17 years, no major issues at all, they loved (and still do) each other very much, and that still couldn't change him.
Hiding or denying who you are has dire consequences for everyone involved. No good can come from this and shame on TLC for promoting it. It breaks my heart and is obviously something I will never watch.