I'm where you are at the moment. We've been having sex for over a year, and it just gets harder and harder each day to stop.
I don't know how long you've been having sex, but we did it sooooooo much for the first few months (I can remember a week where we had sex more often then you're describing lol), and now it's just every so often. I guess the novelty has worn off. So, if you haven't been having sex for ages, it's probable that you're not actually 'hypersexual,' but just in that honeymoon phase.
I understand that it's definitely not as easy as "If you truly don't want to, you won't" or "Just don't be alone together." The spirit may be willing, but if you've been in such depravity then it's not very likely that your spirit is filled with the strength of God's Spirit. Which means that your spirit is weak, and your flesh will find ways to fulfill it's desires.
I think, most importantly, both of you really need to want to stop. A rope of three cords is not easily broken. If it's just you who wants to get back with God, then it's not going to work while you're still in a relationship like the one you're in. If your boyfriend doesn't want to stop, then it may come down to choosing between him and God. If he does, then you're very fortunate.
I think that the key is in building your relationship up spiritually. There are three components of a relationship, yeah? The physical, the emotional and the spiritual. The emotional tends to grow regardless, but we often find that, in an unmarried relationship, one of either the spiritual or the physical needs to be dwarfed. You can't have a relationship that is growing spritually, if you're nurturing the physical. And if you're nurturing the spiritual, then the physical will grow steadily behind it, but won't overcome it. With that in mind, I think it's a good idea to spend time with God together, feeding that side of the relationship rather then the physical.
I also think that it's vital to set clear boundaries. Yes, it's clear that you don't want to have sex at the moment. But what constitutes as sex? And what about things that you know lead to sex? I like the idea of the rule that says you should consider how you'd feel if someone touched your husband in such a way, and go by that. But I know that, especially after having had sex, I would not be able to go with out kissing, hugging and holding hands. You need to sit down with your boyfriend and prayerfully consider 'How far is too far?'
It's possible that you may need pastoral counselling. My boyfriend and I are looking into it, because it's getting to the stage where we just can't stop, no matter how hard we try. Similarly, I suggest you get people you trust to pray for you. The prayer of a good person can make a lot of difference.
I have a post very similar to this, and it looks like I just answered my own question, haha. Feel free to send me a PM if you'd like to talk about this with someone who is going through the same thing (I know I'd love someone who actually understands to talk to about this, haha). Remember that God doesn't tempt us beyond what He knows we can deal with.