Ummm, no. It wasn’t because they got married outside that caused the fall of mankind.
I was being silly. I was HOPING you were being silly.
You want your serious answer?
The Church is supposed to be a “foretaste of Heaven.” Adam and Eve were in paradise. They rejected that paradise, and were expelled from it. The Church is sign to us that we will someday be with God in Heaven. Adam and Ever were already with God.
If your local parish church doesn’t inspire you much, well Catholics CAN find churches that are more inspiring. But whereas your local parish may be very inexpensive, (ours was free, because we found our own cantor, organist, etc.), you might have to pay... significantly if it’s a grand church with high maintenance costs and high demand.
Yes, God is outdoors, too. God is everywhere. But each church contains the tabernacle, his chosen dwelling place among Man. And choosing to mark your marriage with that sacred place signifies that you are putting God front and center in your marriage.
Now, Catholic masses can take place outdoors, if there is an extraordinary issue. The Pope frequently has outdoor masses simply because the outdoor venues are larger. But that’s a special circumstance where a church is inadequate, not that the Pope doesn’t find churches to be beautiful and sacred in a special way. There are also certain venues which are designed to regularly permit outdoor services. But don’t be cheesed off if they don’t play along with being used as a loophole.