« Reply #2 on: Wednesday 20 January 16 08:18 GMT (UK) »
In legal terms, your mother, being the product of a bigamous de facto relationship, was illegitimate. You are the product of your mother and father; if they were married, then all is straight forward. If they were not married, then you too are illegitimate (legally). In this day and age however, it all gets a bit grey.

I am Australian, from all the lands I come (my ancestors, at least!)
Pine/Pyne, Dowdeswell, Kempster, Sando/Sandoe/Sandow, Nancarrow, Hounslow, Youatt, Richardson, Jarmyn, Oxlade, Coad, Kelsey, Crampton, Lindner, Pittaway, and too many others to name.
Devon, Dorset, Gloucs, Cornwall, Warwickshire, Bucks, Oxfordshire, Wilts, Germany, Sweden, and of course London, to name a few.