I think generally over 45mm nut width tends to be considered wide. I only play wide-neck acoustics and I find 43mm too narrow: the two Recording King guitars I own both have 46mm nut width and I find that perfect.
I've heard it said many times that nut width is not necessarily an indication of string spacing but I have never once playing a 43mm-nut guitar that had wide string spacing. Never.
Thomann's Harley Benton range do a surprising amount of wider nut widths. There's the one I linked to above.
But there's also this 45mm 12-fret-to-body parlour that I will inevitably buy one of these days, it's just too tempting: cheap Early Benton mahogany parlour