Reading your post is like reading my own life story in brief. I also have a happy and healthy family, and work hard to give them the best and to ensure that they want for nothing. My upbringing was also quite frugal, I had a single mum but also an available dad with no ill will between them.
Something I have come to realise though, while over working myself more regularly than I would like to admit, is that I am really just giving my family the things that I want for them, because of my own feelings of inadequacy, not necessarily what they want or expect. Our children really just want loving parents, they want our time, it’s as simple as that.
They may get accustomed to toys and other things, but we beat ourselves up too often trying to ensure they have the best of everything, fuelled by a media that encourages this sort expectation.
What you describe is like a form of ‘imposter syndrome’. I think many of us look at ourselves this way from time to time. For me, I reconcile it with the fact that I am not perfect, and NOBODY is. So we all have a little imposter inside of us. It certainly does not mean that we don’t deserve the things that we have.
Good luck on your journey!