Okay, so maybe saying that this will save your marriage is dramatic, but if your spouse likes the squeeze the middle of the tube, here's a way where you can prevent being annoyed every morning...and they can squeeze wherever they like.
Binder Clip, meet Toothpaste Tube.
Seriously, it wasn't driving me that crazy since we've been married...only since we bought this giant toothpaste tube and something had to be done. I don't know why it came to me, but one day whilst cleaning I came across a binder clip and thought to put on on the end of the toothpaste. It seems to be working so far, I only have to roll the tube up again every day or two.