EU Succession Regulation 650/2012

I am 75 and on my third or fourth wife (one loses count).  She is 50.  I have one legitimate son and an illegitimate daughter. My wife has a son by a previous marriage.

I have made separate provision for my daughter and intend to exclude her from my estate.

I am a British National., live about 5 months in Spain and 5 in USA travelling the rest. My assets are in Spain and US. 

My domicile of origin is England.  My domicile of choice is Spain.  I am certainly not “deemed”  domiciled in UK.

When I die I would like my widow to have a life interest in my estate and then it should pass exclusively to my son. 

How do I go about  achieving my objectives?

Make a will with the proviso "I wish this will to be executed as per the laws of my nationality which is UK" or summat like that. Can't remember the exact wording but that way you can leave your estate to whoever you want.

Even if you become a Spanish resident (ie living here more than 6 months of the year) that will still be valid.

You make a Will in Spain before a Notario,  who, when you explain what you want,  will know what to include.

The right of usufruct.  Life occupancy,  is explained in Eye on Spain in a blog at:-

 Spanish wills and inheritance taxation: The Usufruct, a way of saving taxes