I don't know how relevant this will be for you or your story @GlitterRain7 but here is the marriage concept that @Maggie May referred to. https://en.wikipedia.org/wiki/Levirate_marriage Here is the "female version". https://en.wikipedia.org/wiki/Sororate_marriage
To clarify my issue: - I don't have a problem with getting married at 18--that is, I think it's unwise, but I don't have any "taking advantage of a young person" problem with it, just a "you're kind of stupid at that age; why not wait?" problem with it. - I don't have a problem with marrying your sister in law. I have a small problem with combining the two, especially if the man marrying his sister in law is substantially older than her. Again, I'm not saying it's OH MY GOD WRONG!, I'm saying that there's some risk of some eyebrow-raising.
Yeah, I can certainly see where it might be an acceptance problem if there is a large age gap and/or a too-soon-after-death thing. Or, of course, if the younger sister is underage—then it's really not on at all. The remarriage thing is a separate issue from the married-at-18 scenario, I reckon. As you say, it might not be wise for the original couple to have married that young. But then again ...sometimes it works. And sometimes it doesn't. But that can be said of marriage at any age, really.
Oh, yeah, I'm not saying that young people shouldn't be in relationships because that would just be silly. I guess what I'm trying to say is that regardless of how well put together someone is in high school, there's always going to be some sort of change in perspective of the world and themselves and how they fit in it. And when you've got a relationship where one member has already gone through this and the other one hasn't, it can cause some serious relationship problems when they do. I'd also say the gap between a couple where one person is 18 and the other is 22, is far greater than a couple who are 21 and 25.
I just looked at their birthdays, and the MC is only two years and a couple months older than the sister in law. Actually, the late wife - though they were in the same class in high school - was several months older than him. If the MC had not ended up with his late wife in high school, it's possible he could've ended up with her sister as she was a freshmen when he was a senior. That scenario happening is a bit unlikely in my opinion, but still possible. The sister in law will be the one who starts the romance between them. She's looked up to him since the beginning pretty much because they both have depression and he tries to help her deal with hers. They're both going to go through some other stuff before they actually have a romantic relationship that they'll end up helping each other through, as well. I, personally, feel better knowing it'll be her that initiates it rather then him since she's the younger one.
What's kind of funny is what happens at the other end, and I know a couple of these as well. Unless they go on having many children, their child-rearing days are done by the time they are in their mid-thirties. So they are ready to ROCK! Sometimes this can mean they want their teenagerhood back that they realise they lost out on, which can result in marriages dissolved, etc. However, it often simply results in a very young outlook, which, as they get older, can result in looking foolish OR being really charming and exciting people. When I feel sorry for them is if they then get saddled looking after their offspring's children while the offspring go to work. They become grannie/grandad 'parents' again. That's just not fair, is it? Unless that's what they want to do.
