Hey there.
I actually got to live in Rome for about 3 months for a study abroad program, so I'll add my two cents to this post. I definitely second the trips to Florence and Venice, especially if you haven't been to Italy before. They are what people dream of when they think of Italy. Also some day trips from Rome:
Go to Tivoli to the Ville D'Este which are also known as the Gardens at Tivoli. Thats where they have the wall of 100 fountains (If you're really gay, thats the wall of fountains that Hilary Duff ran by in the Lizzie McGuire movie). Its gorgeous and close enough to the city to where you can leave a little later, like noon, and make it back by six or seven.
Additionally, if you're into ancient ruins there's this little abandoned military city north of Rome that's been there for hundreds of years. It's called Ostia Antica. This is another day trip that you can take, leave a little earlier like 9 or 10 and be home by 6 or 7. Mostly because you want to explore on your own. And since you're going with your partner, you might be able to find a temple or something to get up to some shenanigans in.

This was one of my favorite things to do while I was there, and not that many tourists know about it.
Also, make it a point to check out some of the churches. I'm not religious, but some of the artwork they have on their ceilings is truly breathtaking. Check out the Caravaggios, and there is a church on Vittorio Emmanuelle 2 that is right near the Campo Dei Fiori and the Pantheon that looks like a dungeon from the outside, but has one of the best ceilings in Rome. Ah! and there's a church down by the Colosseum where you can go deeper and deeper underneath the church, seeing at each level the churches that were built on top of each other. Bring a jacket because it gets cold underground.
For going out, there are like 4 gay bars in Rome, two of which are down by the Colosseum. I exaggerate, there are more, but I couldn't find them. The younger crowd goes out in Testaccio now, which is right next to Trastevere. Its pretty fun and I heard of a great gay club in that neighborhood while I was there.
Wow... I went on for a while. I hope this helps!
Ciao bello.