This is a tough thing, as deeply ingrained as the mormon religion is into our families. We are dealing with a similar situation right now, but in reverse, I guess you might say.
My oldest son is 20. After hemming and hawing about it for a year and a half he didn't go on a mission. He stopped going to church once he got out on his own, and has recently moved in with his girlfriend, who has separated from her husband but whose divorce is not yet finalized. Now she is pregnant. He pays lip service to the church, and claims he goes now and then, but it is all a smoke screen so we don't come down on him, which we haven't done.
And so we (my wife more than me) struggle with the idea that somehow we failed him. He didn't get something he needed or in some other way we screwed up. But I think that is a cultural thing, and partially based in the dogma of the religion, that we fail our children and in our personal development if our kids don't make the "right" choices, so it cuts close to home in more ways than one, and that attitude is one reason I have distanced myself somewhat from the religion over the years.
When people hear we have a 20-y.o. son, they ask when he gets home from his mission. When we tell them he isn't on a mission we get the whole "oh, well. that's um...well you know everyone has...ok...um <awkward laughter and throat clearing> hey look, someone brought jello!" No one knows what to saw and the sideways glances are inevitable. It bothers my wife a lot. I let it mostly roll off, but largely because I already know the LDS church is one of the most judgemental groups (culturally) I have ever been associated with, so I expect it and just roll with it. But she feels like she failed as a parent, and the reactions she gets from church members reinforces those feelings of failure.
Our daughter who just turned 18 and graduated from High School this year was far more active than our son and has been talking about a mission for the past 2-3 years, ever since she went to EFY. That is, until her boyfriend of 2 years, who is going to BYU Idaho, decided he wasn't going on a mission because he doesn't know if he even believes in God and started pressuring her to come to BYU Idaho with him. She now wants to transfer there instead of go on her mission.
This has my wife in tears almost nightly. She feels like she is losing all of her kids. Granted, we have been far from perfect mormon parents, but we have always encouraged our kids to find out the truth for themselves. They have all read the BoM, most of them more than once. They all participated in all the youth activities, etc. We have been probably 75% active over our marriage, with the biggest drop-offs during 9:00 am block times as 9:00 am is TOO FREAKING EARLY FOR CHURCH. 11:00 is perfect.
We have tried to do the "right things" with probably an 60% rate of FHE and family prayer and scripture study. Regular monthly date-nights with each kid we go over their goals and what they want to do in their lives and stress the importance of mission and temple marriage, etc. Father's blessings and other blessings as the situation may warrant (illness, start of school year, tough time in kids life, etc.)
But in the end, no matter what you do, or don't do, they choose for themselves what they believe, and they will act on it as part of their own free agency. It is hard to get my wife to see this and recognize all she can do at this point is love them, provide wise and loving counsel, and accept them for who they are. So we try to teach them correct principles and let them govern themselves. Sounds good, but in this culture, where you know you are being talked about, and often looked down on, if your family doesn't meet the high requirements set forth by the unwritten rules of mormon societal norms, it doesn't hold a lot of water. The sins of the sons will be answered on the heads of the fathers, so to speak.
Is it really any wonder, in a culture with pressures like that, that is so all-pervasive, that when people do pry themselves away from it, depending on how deep they were in it to begin with, there is going to be bitterness and anger and lashing out, as it would feel like you are tearing yourself apart at the core, and the church would be to blame.
