badlydrawn and poshbird make some very good points.
OP you have young children, they aren't that age for very long. All too soon you'll be looking back nostalgically at how they've changed and grown. If you think of your life as 75 or 80 yards of ribbon, the length of it which represents these years raising your family with your wife, watching your children grow and mature, is really quite short.
If you're happy living with your children, happy in your home, you and your wife get on - isn't that enough for now? I think you have become obsessed with the notion that there is one piece of a jigsaw missing in an otherwise perfect puzzle. You can either admire what you have helped to create, disregarding the one imperfection, or throw the whole lot up in the air, move on and get yourself a new puzzle to work on.
If you are constantly giving off vibes of dissatisfaction, lack of contentment and even resentment, that is going to be a real turn-off for your wife. You describe feeling that you have been "conned", which I have to say I think is very unfair and self-regarding. I wonder how much of that feeling seeps into your everyday relations and communication with your wife?
Would you be happier if you were having great regular sex and had a lovely home but no children? Or having great sex with loads of children, no paid work and living in cramped, unsatisfactory accommodation? The obvious point here is, not many people have a wholly satisfactory life - and there is often very little they can do about it.
She works, and you say she loves spending time with the children. Your children are young, so your wife's life is pretty full-on. Often as a mum I feel I only have so much energy for emotional engagement and intimacy, and I usually feel as though I am managing ok, but running with the needle hovering above empty. I think when you have children most people feel like that. You find the energy, somehow, for the things you need to survive - and for your wife, as for many people, sex just isn't one of them.
I think you have to decide whether you can happily make a go of it and appreciate what you have. Of course you will want certain areas of your life to change or improve - that's part of life - and indeed things may change and improve. Who knows what emotional/hormonal/psychological/pshycial issues are in play with regard to what your wife thinks about sex at this time of her life.
It's not as though your wife doesn't want to have sex with you but would still like to have an active sex life. She's not having sex with you because she doesn't want to have sex.
I think you need to think seriously about whether you can settle for the otherwise good life you appear to have - or whether you want to make the whole family suffer emotionally and financially for years to come, for the sake of your dissatisfaction with this one area of your life.
Can I suggest you go and get counselling yourself. That would give you a chance to talk through the problems as you see them, and how you communicate with your wife? It may help you to see whether you wanted to pursue couple counselling, or to make up your mind what you want out of life.
I think you need to make a decision about whether you can be happy living your life the way it is, or whether you'd be happier leaving. Either way there are consequences you will have to face - not all of them easy or happy.