What do I have to do, is there an underlying issue here I'm missing ...?

This all started some three to four years ago as my lovely wife approached the magic 40yr old mark and was diagnosed with type 2 diabetes, at the time we were also running our own business with the stresses that go with it.It seems since this time things have deteriorated between us for reasons I cannot not fully comprehend as we have only argued as normal married couples do. She started working nights after we lost our business and has done ever since, in the restaurant game, while I did Mr Dad with our girls every night after work re; homework, cooking dinner cleaning up doing the washing and generally the whole nine yards thing so as to keep the balance in the house hold.Since this time I have been asked to leave the house on my fifteeth birthday with out even a kiss or a card, was not allowed to share her forteeth birthday with her, as she did this with new found girl friends has not allowed me to touch her ,kiss her, cuddle her nor sleep with her. Our children have now seen their father sleep in a seperate room now for just on 12 mnths, even they think this is strange. 90% of our time we do spend together my wife and I, it is as if there is nothing wrong. When we start getting to close she seems to go into rejection mode again as was the case two weeks ago when we were all sitting down watching TV and I was massaging her legs and feet like a loving husband, she woke the very next morning and handed me divorce papers to sign...? She is as I'm typing literally packing up her belongings and the childrens to move out to her parents for a while, whom live 3500kms away, she has no money,no job and no where to live, she has nothing planned for the children 7 & 10 other to take take them from their dad,their home, their school not to mention their puppy and all because we sometimes argue. She refuses to communicate nor address the issue with me except to say it's over and wants to move on, there is no third party i'm sure, so could there be new tendencies,,? I don't know, as she has become quite fashionable of late considering the circumstances, and is becoming more and more secretive by the day..? I'm a good farther and a even better husband in great shape with a great job yet this does not compute anymore,the kids are about to lose everything they love because of their mothers very selfish agenda, and for what..? hence the $64 dollar question.. what am I missing here?