I can speak to the marriage/family question as both a daughter who's father left and a single adult who's deciding how she feels about the church these days.
On the side of watching a family member leave, yes, it's hard. It was scary for a while. I blamed my dad. I was mad. But I am now closer to him than I ever was as a teen. He was my seminary teacher. He had been my favorite adult when I was a little kid. I idolized him. But he was very traditional and as I grew up, our similarly stubborn natures caused a lot of friction. I tell my mom regularly that I prefer my not-a-Mormon dad to my Mormon dad. He respects me more. He listens to my opinion. Some of this may have been a natural part of growing up and redefining my relationship with him as an adult. But looking back at seminary teacher dad, the me I was even when I just graduated BYU (and I will never back down from the certainty that Provo is best) would not have gotten along with him as well as I get along with him now. I have friends who were taught one parent was the cause of all the problems and yet they came to be closer to that parent in the end. What I am trying to say here is that kids don't always do what's expected. Give them a confident and self-assured example in a good life - however you define that - and you've done the best you can.
For the record, my mom and dad met at EFY, she waited for him on his mission, they got married in the temple, and held all the callings. It doesn't matter where you start. It's going to change.
That leads into my perspective as a single adult. I honestly think it's better going through this now. Not to get to the end of the journey - that won't happen until I die - but to know that it's something I will struggle with. Ever since my dad left, I wondered if I would ever reach this point. He and I are so similar, it worried me. Turns out, my reasons for asking these questions are totally different than his, but I am still asking. I've tried dating in the church. I have found that I actually can't handle most Mormon Boys. They just aren't people I care to spend a lot of time with. I'm starting to date outside the church. That has all it's own issues (which I'll probably post about at some point), but it's the route I'm trying right now. I mean, if you aren't sure you're sticking around, does a temple sealing even matter? For me, I've thought for years that marrying an RM wasn't an issue for me. Now I'm thinking a sealing isn't a huge issue either. My best friend has nearly 4 kids who - as of now - being raised in the church. If I really care, I can arrange to have it done when I'm dead.
Wow, that was more words than I meant to dump here. But your post really struck home for me and I wanted to start sharing. Thanks for coming here.
Public forum for those seeking support for their experience in the LDS Church.
I don't think there could ever be just one single philosophy or one single religion. Since there are so many different types of people, with a range of tendencies and inclinations, it is quite fitting that there are differences between religions. And the fact that there are so many different descriptions of the religious path shows how rich religion is. - HH the XIV Dalai Lama