How to I cope ?

Well my situation is that I have been married to a Dutch man for some years and have lived in The Netherlands with him for just over 10 years. Anyway during the past 4 years I have been thinking of leaving and returning to England, my home country. I have one son with him and a daughter from my previous marriage. My dilemma is having the courage to walk out the door. Thing is I do know that our marriage has run its course and there has been no cheating on either side. He can be very self centered and thinks of himself alot. Anyway I am taking the kids with me later this month for a 'holiday' in England and I am trying to gather the courage to just stay. My problem is as I am waiting for this time to come, I sit at home alone, have not one friend here, very isolated and start thinking and thinking. I get very upset crying and start to feel guilty and worried, deep down I know its the right decision for me to walk but I just dont understand these feelings I am having now. If I imagined returning to Holland after this holiday then I feel extremely downcast. Am spending these days crying, not sleeping and of course he asks whats wrong and I am trying to put an act on so he wont guess that I may not return. I am just so distressed and feel totally alone with all this.....