Because they've been brainwashed to believe that marriage is an essential part of life, and that once you do it, it's desperately important to hold it together "'til death do us part" -- which is unfortunately what probably happened here. Since they're so committed to the idea of getting/being married, they blind themselves to the real character of their boyfriends/fiances, who are generally showering them with romantic nonsense before the marriage. Once married, when things start to get unpleasant, they go into the "marriage is forever and we just need to work on it" mindset, for which they will receive plenty of support from society at large, and the LDS Church in particular. They are also convinced that "trusting" people is a virtue, and they are especially convinced that spouses can and should "trust" each other, so they "trust" their scumbag husbands, never verifying odd things they notice, and just plain refusing to notice red flags waving wildly.
It's a very dangerous and very common approach to life among women. Laci and Lori are just the extreme, highly publicized cases; there are literally millions out there practicing this mindset, and ending up getting beaten, watching the kids get beating, having the family finances frittered away by the husband's extracuricular activities, catching STDs from their trusted husbands, etc.
It's not just LDS.
I'm LDS and I'll tell you one thing. My husband lays a hand on me in anger and he's gone. I'll forgive him once, it happens again, and we're done. The LDS church does NOT condone staying with abusive spouses.
That said, there is a lot of pressure to make one's marriage work, especially if it is a temple marriage. I know several people who have stayed married in spite of the bad times, but none of the problems involved abuse, either physical or sexual. Most managed to work through the problems and are now happily married. Others got out, and I can't blame them at all.
Truly a dose of reality. What you said does occur frequently.
I can't remember how long these two had been married.
I am thinking maybe a couple years?
Laci and Scott Peterson were married for 5 years b/f she was murdered.
Sometimes I have thought about the high rate of divorce, and it's sad. Like many others, I think about how part of the reason for it is that divorce is easier and easier to get.
But then one has to step back and think of how it supposedly was in the "olden" days. Seems to me that if divorce is very hard to get, that might lead to an increased incidence of spouses murdering spouses, since that might be the only way out of a terrible marriage.
Nowadays, it seems that if it's just two people, divorce is the answer to a miserable union. But what about if it's 3 people? Things have changed on that front, too--just in the last 20 years. The federal government has set "guidelines" for child support. They are serious about enforcing it.
Nothing wrong with making sure both parents pay for their children. But... it's very hard to get out of. Nowadays, a child support obligation is like marriage used to be: almost impossible to avoid, once that child is born. (I'm not saying they SHOULD avoid it, I'm just saying some people WANT to avoid it.)
Both Laci and Lori were pregnant. It makes me think that the husbands saw something coming that they couldn't get out of.
It also makes me sick that a potential money problem would, in their minds, outweigh the potential good of having a child.