Colleague???

Or "bum chum" maybe? 

While I do think collegue is a bit peculiar, they probably didn't want to presume you are partners. I met a couple of " friends" on boats this year whilst I thought they where gay I didn't know. So I wouldn't presume to call them a couple without knowing.

No - I think colleague is a weird word to use in the context of two blokes obviously enjoying leisure time together. It is vanishingly unlikely that it would be used for a male with a female in the same circumstances (unless at least one of them was holding a clipboard at the time.

I would use "mate" - wonderfully ambiguous.

Why not just say 'boyfriend' or 'girlfriend' (if not married)? Seems simple enough to me.

Interesting, not sure what I would have called him, your friend probably.

I know people call K who crews for me, your partner. She is not, just a good friend.

I think people are frightened of offending so for two males maybe colleague is a safe word.

Maybe you are getting more approachable. Hence people are trying to get things right.

I know a female partnership where they refer to the other as husband. Can't get my head round that, husband is male in my old mind. But hey I claim old age as my excuse.

Interestingly when a gurl refers to her "girlfriend" it is not generally assumed that they are carpet munchers whereas if a bloke refers to his boyfriend they are clearly queer as a 9 bob note. Very strange!

But anyway, "friend" or perhaps "personfriend" (to be PC) would be fine.

im reminded of a wedding we went to, very posh affair in Inner Temple Hall in London (my uncle, the groom, was a QC and judge). Mother introduced Jeff to a crusty old family friend as "Nick's partner". Some time and several glasses of champagne later said chap sidles up to me and asks in his Etonian accent "So what sort of partner is Jeff, is he your business partner" to which I said, being mischievously tiddly "no, he's my bed partner" where upon said crusty chap scuttled off to nursey for some medication.