Really? Never saw that in pirates of the Caribbean.
Real pirates weren't much like modern fantasy pirates, although Benjamin Horneygold was somewhat like them. A gentleman pirate (at least to some extent) with a taste for the flamboyant. One of the best known stories about him concerned his piracy of a merchant ship in which he took only the hats of the crew, nonchalantly explaining as he left that he and his men had got stupidly drunk the night before, thrown their hats into the sea because it seemed like a good idea at the time and now needed new ones. He ended up working for the British authorities, a fallback position he probably planned since he had a hard rule of never pirating British ships.
Anyway...yes, really. The real pirates of the Caribbean had a form of marriage open to anyone, regardless of sex. Fully recognised, with wedding ceremonies, automatic inheritance and suchlike. Might be sexual, might not. Probably wasn't most of the time, i.e. it was probably very much like this case most of the time, but it probably was sexual sometimes. Since pirates didn't give a damn about laws other than the rules they made themselves, they felt no obligation to conform to other people's rules.
I had to look up the name, because it's not English and I'm not much good at remembering words that aren't English. Matelotage.