Thank you xI dont think the nature of your relationship with your ex has anything to do with a visitor visa. Its not that you are intending to marry your BF if he comes over for a visit (and I'd advise against even considering this option as its part of HIS visa conditions) so I dont even know why your "relationship status" even comes into it. I think you are over-thinking this
But how to explain why some documents are in my married name and why some are in my maiden name?
i mean the required documents he will need to provide e.g bank statement , passport ,house contract...?