Well, this aspie loop is very usual. You must get used to it, since this is not gonna change.
What should you do? I would suggest to apply the concept of 'fairness'. Aspergers (usually) give a high consideration to 'what is right' or 'what is fair'. So, let's say, if he's in his aspie loop and he doesn't pay any attention to you, but at the same time he expects that you'll be there when he'll get out of his aspie loop, that's not fair.
On the other side, if you expect that he gives up his special interests, this is not fair too.
So you can play the card 'fairness' to ask for a middle point.
Aspergers like rules. I would suggest, as an idea, to deal a middle points as, for example, every week you can interrupt him X times and he has to give up whatever he's doing and dedicate to you. Moreover, you could even do X small cards (both of you agree the number), that you fill up every week to the agreed limited number, with some text like 'A free amazing soiree coupon'. Then, whenever you feel lonely and he's in his loop, you slip subtly one of these cards in front of him. 
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1 part of Asperger | 1 part of OCD | 2 parts of ADHD / APD / GT-LD / 2e
And finally, another part of secret spices :^)