I don't have any suggestions, but some advice. I agree, it will be nice to do something special with your SO, but when I'm with my Fiance, I always prefer to do normal stuff. I hate having days filled with an extensive itinerary with special things to do because about half way through, I want to go home and snuggle and laze around. Our first two trips together were very action packed, but the next three were much more relaxed and simple and we actually prefer those.
Obviously, you should feel free to do whatever you want and spend your time with your man however you want. You know him and your relationship with him far better than I do. My main point is that sometimes just being together is all the special you need
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, so I wouldn't worry too much about what you're going to do. I'm sure a day devoted to some interesting tourist sites will be fun or showing him around some places you love.