That's a bit silly, because happiness is not a boolean.

He doesn't imply it's a boolean. He suggests to pick a local maximum above certain threshold.

Yes, and that threshold is the boolean I'm talking about. He says

"Marry the first person you meet whom you could happily be married to"

Which implies that for each person, either you could be happily married to them or you could not be happily married to them. My point is that there are probably many people who you could marry and increase your happiness, but that doesn't necessarily mean you should marry the first one you encounter, because of the significant opportunity cost.

Worrying about "opportunity cost" is maximizing, and people who maximize are less happy than people who satisfice because instead of enjoying what they have, they worry about the possibility of getting something better.

It seems that satisficers would only be happier if they are good both at setting their threshold and at predicting the happiness of each option. And of course, setting a threshold requires a consideration of opportunity cost, so you don't get to hand wave that away.

Satisficers don't care whether there's a potentially better option though. That's the definition of satisficing, and it makes most consideration of opportunity cost go away.

You're quibbling.