Sorry, but are you even close emotionally and romantically? I assumed as much as you have said you are both 100% committed.

But how come you can't do things together on such a mature stage of relationship with 100% mutual commitment and marriage plans? What 128 miles have even to do with it?

Do shopping together. Come to each one's house and share chores. Pick up each other after work. That's just from the top of my head. You yourself should have more relevant list of possibilities. Living together is not about sex.

Are you sure the relationship is healthy partnership and not you exploiting your fiancée?