RootsChat.Com

Hello,
I am a beginner in searching my family history. I have really enjoyed the last few months finding out all of my family history using an ancestry website but the main reason i started was to try and solve the mystery of who my Grandfather was.
My Grandmother (who now has dementia so cant help with any questions) has told us in the past that she married my Grandfather and that he was in the army. She gave birth to a son, my father, in 1942 and the named father on his birth certificate is Roy Henry Blakeway.
In 1944 she gave birth to a daughter, and the same father is named on her birth certificate also.
She later remarried in 1945 and on her marriage record it states her surname as being Blakeway and her marital status as widow.
She later married another two times and all the marriage certificates i have been able to find on the ancestry website except the first marriage to Roy Henry Blakeway.
I have also searched through the website for that name but found no one by that name.
I tried to order a marriage cert from the local records office in the area she would of possibly be living but it turned up with no records.
I have also placed an order with the records office for England and am waiting to see if that brings any result.
Many years ago my Grandmother gave my father an Army service number which didn't exist in records held by the Salvation Army.
My father always thought that his father may of been a foreign solider based in the local area as there were allot of American air bases but the dates don't really tie up, especially if this Roy Blakeway was to of fathered two children, would he of stayed in England that much time?
So now i am asking questions, Did she really marry? Is Roy Henry his real name?
Being a novice in this family search business i don't really know what to do next.
Please if anyone has any suggestions especially in the history of that era... were there any other foreign soldiers in the UK, especially norfolk/Suffolk area at that time?
Thank you