Give him a very very special day. I'm a guy too but hope I can help. Something special and romantic for a man is the question.
Maybe try these steps, be the "Guy" for the day.
1. Dress up beautifully.
2. Rent a really posh car, insist that you pick him up. (Surprise him!)
3. Bring him to a posh restaurant and treat him to a fine dinner =)
4. Spend some time with him alone in a romantic place, then give him a present! (Be bold, a new pair of boxer shorts with your name on it will be sooo cool! Well, it also helps to keep him loyal, if you know what I mean

) Personally, I like a more quiet places like an islotated part of a beach rather than a place with lots of couples.
5. Book a room at a 5-star hotel, cuddle each other and whisper sweet-nothings till you both fall asleep zzzz....
Well, it prob will cost a lot but I think it'd be the most memorable thing a woman has ever did for him. However, guys have very different views of things that are romantic. To some guys being romantic isn't even in their dictionary. So it is left up to the women to show the man what romance really is.
