It’s upsetting.

I wonder who would be making a final decision of letting you go. Wouldn’t it be CEO? Even if they complained to HR, HR is not above them or above CEO. HR doesn’t make decisions about fire or hire but they could alert higher ups. Why did CEO signed up on that? Or is there anyone above him?

I know of few people who sued over unlawful dismissal from a job (one at my work one at my husbands and one at a friends place of work). One lost the lawsuit, one was reinstated and one won big money settlement.

If you believe it was done incorrectly (for example is there a policy that you have to be written up or receive additional training if you don’t do the job right before being let go and they violated it) maybe it’s worth trying to fight them.

Overall I am a bit taken aback with your CEO. He though nothing of letting you go without offering extra training but thought it was fine to have long chit chats about your marriage, inviting you to drinking lunch and asking you to his cottage. Yet he’d not bother to look into why you are being let go. I know he won’t tell but I’d be tempted to ask why exactly you were let go.

You can frame it as wanting to make sure you don’t repeat the same mistakes in other jobs. If he thinks it’s ok to do all other creepy things, it should be ok to explain what happened to you