Shall I fire our housemaid?

you cheated on your wife and tht's a bad thing , but at least you realized you did wrong .Now the important part is correcting your mistake and moving on. You know for a fact that if the maid continues to work at your place, your going to get tempted and make the mistake agian.Today its a mistake ,dont let it lead to an affair. If you want to save the marriage ,do the appropriate thing and let her go. If your feeling bad that she had to loose her job because you cant handle yourself ,You could help her find work ,that way your mind will be at rest too.

I think you should fire her but make sure that she gets a handsome pay for getting fired. Make sure you don't see her again too.

You've already done the wrong theres no point in making it all the more worse for yourself, I'd say first you gotta come clean and tell your wife, she'd probably cry her heart out but I don't think she'd end it with you. Then try and talk things through with her, the longer you wait for her to find out, and especially if she finds out the wrong way, the worse the situation could be, and theres less chance of forgiveness that's how it would be for me anyway.