First of all, don't assume that your boyfriend even knows what he's talking about. If you take everything he says literally, it's really going to hurt. In reality, I would bet that he's really stressed and confused, and when he was talking to you, he was trying to define what he was feeling for himself more than he was trying to define it for you. Or, maybe he knew what he was trying to say but it came out all wrong. That happens all the time. Why else would books like Men are from Mars, Women are from Venus be so popular?
After a number of years, what used to be really exciting can lose its flavor, and maybe your boyfriend is misinterpreting/misdescribing a desire for diversity in your sex life together as him not being attracted to you anymore. I'm sure some people find that difficult to distinguish, though they're obviously different things, and he went about explaining it all wrong. From what you say, you have a pretty healthy sex life, so I honestly doubt that he's not attracted to you at all. If all he wants is something fun and different, that can be achieved in a whole lot of ways, and it can be fun trying new things out!
Also, realize how stressful it is for him thinking that this awesome girl is willing to leave her life, career, and friends where you're living right now to move to a different country with him. And appreciate the fact that he wants you to be as happy and independent as you could possibly be. He's thinking that he has to provide all of these things for you if you go with him -- what a responsibility, especially since you two are still in your freedom phase! That's the sort of commitment you see from people who already pledged to spend their lives together. Perhaps it would help to reassure him that you're an intelligent woman who's making a decision for herself, and even though it's scary, you're looking forward to the challenge. And if it doesn't work out for you, you can always move back home, either maintaining a long-distance relationship, or not -- whatever the situation calls for. Even though you see yourselves together for a very, very long time, as an adult, I'm sure you also realize that nothing in life is guaranteed. You both are responsible for your own happiness, and that won't change just because you both get a Visa in Spain, or whatever.
All this stress might have blown the whole attractiveness thing out of proportion, in fact. Sometimes, when someone is stressed about one thing, they take some tiny little detail about something else and let it consume them. And, when a guy is really stressed, yeah, it can also throw his sex life for a loop.
The big problem with being in a committed, long term relationship when you're young is that these various life stresses come and go and can really wreak havoc on the two of you until everything settles down, and you enter that period where you know where you want to live, what you want to do for a living, what it's going to take to be content and happy in life. You know, the point where some people decide they want a mortgage, wedding ring, kids and a dog. You probably have a roller coaster ride ahead of you, but it sounds like you both trust each other and are willing to communicate about serious issues -- even if they come out wrong.
Just don't get into the trap of believing that things are your fault. By doing so, you're taking a huge responsibility, where you believe that you can single-handedly fix all the problems in your relationship. This isn't the case. Just be patient and try not to automatically jump to the conclusion that things are your fault, even if it sounds like he's painting them out to be that way. As your relationship matures, you'll start to recognize the way stress makes him act. And unfortunately, stress makes some people act out in really confusing ways.
Good luck.
