Well if I hadn't told them everyone, and I do mean everyone: wife, Polish daughter, Polish mother and me would all be a lot lot happier!
Until you died and they found out then, easiest option for you but much harder for them as you're not around to answer the questions for them.
I told you in my first post about how my Dads wife insisted he had nothing to do with his baby and how my Dad agreed. She has spent a lot of her life wondering why she wasn't good enough, why he didn't love her as much as his other children, and it affected her for the rest of her life because she always thought there must be something wrong with her. Like you're planning to do, my Dad just walked away from her to keep his little family with his wife and stepson, and left his Daughters mother to wipe away her tears and deal with her heartbreak, while my Dad happily carried on as normal.
Are you really going to do the same thing to your five year old? You're going to just not see her anymore? Again, it's the easiest option for you, that little girl is innocent and as much as I think you're a selfish shit, she probably adores you and if you do love her as much as you claim to, walking away so that you dint have to be single won't make you happy because her little face crying for Daddy will haunt you every night and you'll just be replacing the guilt for lying to you're wife, with guilt for abandoning a dependant innocent child.
Being single isn't the worse thing in the world, you're wife is angry and I can totally understand why she's saying what she is, she may calm down and change her mind, she may not, and yes we all make mistakes. I've made my share, but no way in earth would I punish my child for them just because I didn't want to be on my own.
Stop blaming the women for your shitty choices, own it and fix it instead of choosing the easiest option, you can still see your polish daughter but it may have to be as a single man and it will take some adjusting but I have a feeling you are like my Dad, all me me me me, she made me, blah blah and will take the route that makes you lose as little as possible, and will treat your five year old as collateral damage.
that little girl won't just disappear into history like you're hoping, she may well turn up on your doorstep with some questions once she's old enough to travel? What will you do then? Tell her to fuck off?
I've been on Mumsnet for ten years and this thread has been the first to bother and upset me on a personal level as I've lived through the aftermath and have seen the heartbreak and I know I'll be biased, but for ffs stop whining about how you didn't/don't have a choice.