To think boss and colleague are having an affair?

[ToeSucker]

8 months with a start-up.
CEO is a woman, as am I. Colleague hired at the same time as me is a male.
Since day 1, colleague got treated with extreme preferential treatment. It got more and more bizarre (secret business trips away without rest of team knowing, being put forward for networking events) despite objectively very poor performance. Rest of company are objectively high performers and have increasingly been ignored by CEO.
Colleague also throws tantrums in meetings but there is no HR to work with so everyone just does his work for him and avoids working with him.
I'm not badly paid but I've recently learned this colleague has gotten a pay rise to near DOUBLE my salary.

I realise when writing this down it sounds ridiculous.

Can anyone think of an explanation for this besides an affair? None of us can make sense of it.

She is being blackmailed by him?

Could he be related to her?
You don't say what their ages are.

I'd just leave. Sounds toxic

Not very many jobs around at the moment but I am trying!

She's late 40s and he's early 40s. And I don't think they're related as they are not even from the same country.

Who cares? If you’re unhappy there, leave.

Sounds likely. It’s not them having an affair that’s the problem though, it’s the extremely unprofessional behaviour. It is possible to have a relationship in the work place, even with a direct line manager, and still be a decent human being. You need to get out, as you already know.