I might have missed it elsewhere, but what is your relationship with his mum and stepdad like? Do you know them well? Do they trust you? Also, does he have a good relationship with them?

I don't have a lot of experience with this (I have my first YF ever now and feel pretty close to the way you feel) but I think it's important to keep a dialogue going in all directions. It's hard to keep trust going when one side of the "YF - parents - adult friend" triangle isn't talking, and that can be a serious problem.

I'm struggling with the issue of keeping a balanced life. My YF holds my weeks together, so it was awful for me when we were suddenly pulled apart one weekend. I'm trying to develop some other close friendships but it's taking a while.

About expressing your love for him, you should take your cues from him. It sounds like he already knows you love him, even if you haven't said it explicitly. Some boys aren't comfortable with the words "I love you", but they can still appreciate being loved.