Your fears are understandable, its a new realm, with lots of questions, concerns and expectations

Here is my take.

First is that you have to clear your mind of expectations, and allow things to unfold naturally. The other thing is that sex is more deeply enjoyed in a relaxed state. When the time comes I would recomend starting off slowly. A proper massage is good opening that will allow you to learn and explore each others bodies, and understand aspects of touch that turn each other on, or not. There are a lot of books and videos to help teach the basics, the rest is learning the preferences of the person you are with. Take your time and don't rush. I would suggest low lights and some slow relaxing music softly playing in the background. Sex should be not just an event, but a night of passion, a set of ever engaging opening acts followed by a climatic moment. Experiment with things like scented oil, ice, sweet foods like strawberries, etc..

Also do not worry if the first time is not the bell ringing, firework inducing spetacular event you see in Romantic films, sex is an acquired skill that takes patience, practice and a willingness to learn. If the two of you truly love each other as your post states, you will want to spend a lifetime learning together.

I hope that helps.