Frankly a drink is a drink and that is all.

If i bought a woman a drink I would expect a chat and there would be no obligation attached.

Trouble is plenty of guys think a drink means a chat that leads to more, you happened to meat one of them. He even gave you the set up - single man from out of town on business and at a local hotel. He was fishing and cast the bait. He was expecting more (even though you told him your situation) and was upset when he didnt get it.

Were you obliged to provide more, in some eyes, perhaps. In all reality : No, absolutely not. He was wrong and ill mannered about it. Send down the Russian....