Jeff Bezos and Lauren Sanchez Making Out at Restaurant in Rome

Jeff Bezos and Lauren Sanchez have been going strong for more than 3 1/2 years, and based on the photos ... you gotta wonder if the end game is tying the knot.

Lauren and Jeff were like high school kids over the weekend ... at times sucking down pasta, at times just sucking face.

58-year-old Bezos and 52-year-old Sanchez dined at Aroma restaurant in Rome, the latest stop in their global love tour.

They've been all over the place ... cruising on yachts, hitting up celeb hot spots in L.A. like Nobu, going to swanky parties, etc.

As far as we can tell, they've been living together for a while, so it seems like it's just a matter of time ... Now it's true, some people just aren't into marriage -- they don't seem like those people.