Life doesn't "end" but there are definitely some big changes ahead and some of your biggest struggles as a couple are yet to come. Factors that never existed in your marriage will soon come up and you don't know how you or your H will handle it until you get there. There will soon be a ton more responsibility added to your household and while a lot of H's are great about helping as much as they can, there's also a lot of mommies who end up with the majority of the baby care, on top of the responsibilities she already had.
My H and I weren't married yet when DS came along and I'll be honest, after the first month that DS was born (which was like a honeymoon phase and my now-husband was really helpful at first), the next 8 months or so were hell on our relationship and when I look back I am still amazed that we made it through it without splitting up. Lol. We fought all.the.time and there were a lot of resentment issues. So all of that combined with the lack of time for each other can definitely be challenging. But it's good to be prepared and talk about things ahead of time etc...
ETA obviously this doesn't happen for everyone, but it certainly did for me and many of my friends also had a lot of disputes about the parenting responsibilities with their H's and fought more in the first year or so of baby's life, than they'd had prior to that. Plus I think that sharing of responsibilities tend to be one of the most common things that couples fight/disagree about anyway, regardless if they have kids or not.