Ahhhhh in. The word folds time and space around it. When you are in you are central, immersed, below and above, on and under, at, there and then. To be in is to be floating, and you float in (You also float on, but that usage ignores the sky. More importantly it ignores the argument I’m trying to make. Fish float like experience.)
No wonder we use it for love and danger because we are immersed and we are held whether for years or for an instant. And I was in both, though the danger had more potential. In love requires the love. In danger is the lead up to, the path. You can get rid of the danger and you would still have been in it. Love though, you can’t be in love without the love. You would simply be ‘not in love’, maybe on the way, may ‘to love’ or ‘across from love’, but the potential doesn’t imply the actual. The path is not the destination. “In’ is large like that it can accommodate two contradictory ideas. Another reason we use it for love.
Though in truth I think most people are merely at love.