When is Enough - Enough?

I'm sure this will offend someone. I know. And I'm apologizing in advance. A real, truly sorry, apology. But I have a question. And I'd like an answer. When you are wanting a child, when is "enough" "enough"? I'm reading a story about a woman who has had, at last count, eight - yes, EIGHT miscarriages, and has one child. She and her husband have been through several IVF treatment cycles. It's just not working. Yet, she and her husband are trying yet another IVF cycle. She has one child. She wants another. When do you call a halt? When do you consider adoption? When do you sit down and thank your God for the child you have? When do you consider that, maybe in the grand scheme of things, one is all you're getting? When do you consider that, for some people, ONE would make them "over-the-moon" happy? Disclosure: I've been pregnant 4 times. I've had 2 kids. That's 50/50 odds, and the second one tried to deliver himself at 4 months. I figure I'm done. My body gave me a message. I had two kids, they're healthy, and I lost 2 kids. This was, of course, when IVF was in the time of "Baby Louise" and it was just outside of the realm of a "normal" couple. I have a friend who has gone through IVF. Adoption is, apparently, NOT on the table. They have no children. I don't know where they stand, and it's kind of a touchy subject. You obviously don't want to start a conversation with, "Hey, Sally - you pregnant yet? You still think adoption isn't a good idea?" Of course. That's insensitive. And I'm trying to NOT be insensitive. And I do know what it's like to lose a child. And I do know what it's like to give birth. But I still wonder. What drives couples to continue to do this? And when do you know that your body, your budget and/or your marriage has had enough? I can truly understand "baby hunger." Because when it was my "time" for having kids, it always seemed that EVERYONE was pregnant, except me. Please believe me when I say that. However, I have to say, in all honesty, that if it didn't work out, I would have taken it as a "sign" that it wasn't supposed to work out. I wonder why - and how - couples put themselves through this. This kind of begs a bigger question. Just because the technology is out there, are you compelled to use it? Would you feel that you'd "failed" at trying to be a parent if you chose not to use it, or if you went through "only" one cycle and it didn't work? Maybe these questions are unanswerable. Maybe I'm not meant to know the answers, and maybe it's all just too metaphysical in its entirety. But I still wonder. I would like to think that everyone who WANTS to be a parent can be one. But I read the stories, and I know what my friend is going through. And I wonder.