My partner eats very differently from the way I do, but is a naturally normal-weight person. Some of my weight gain since we moved in together was a consequence of my trying to eat the same way. What finally happened is that I uncoupled our eating. I eat my foods, and my partner eats hers. Sometimes we do put together meals for both of us to share, and that's fun. But she can eat a lot more carbs than I can without gaining. Also, she doesn't tend to overeat, and she just stops eating when she's had enough, a concept I'm still working with.
(Case in point: The Doritos. I buy a bag and divide it up into serving-size zipper bags, which go on a top shelf in the pantry. They are for both of us. She will start on a baglet of Doritos, eat a few with her lunch, and then leave the rest in the baggie, just sitting there on the counter. For days.
)However, I don't think that I would expect that someone else should change their lifestyle to suit mine. I wouldn't insist that someone I was just "dating" should "commit to a healthy lifestyle." Better not to date them!
Jay


Her natural thinness has always baffled me, because she eats A LOT and never exercises, but I just tell myself life isn't always fair.
As I may have mentioned before, we are still best of friends. She went on vacation with me for my bodybuilding competition. That weekend, we both went out to eat and then ate lots of other junk. I felt horrible, but she said, "Why are you so sick right now?" I said, "I've been a total glutton, I can't believe you're not feeling it." Her: "This is how I always eat. You know that." 

What excellent, beautiful pictures! I would LOVE to go to Italy; it looks like you had a great time.
Then again, it depends how cheap you feel, I suppose. I have an easier time on the tredmill too, in the sense that if I don't keep up, I'll fall off.
OOOOOF! After running 3 hours on it one day (I had too many excess calories during my bodybuilding preparation and needed 'em gone...quickly), I have lost interest, though! 