(Not+to) or (to+Not)

[saloom2]

Hello everyone,

I'm sorry to not have written earlier.?

or

I'm sorry not to have written earlier?

WHY?

THANKS in advance.

 

[5jj]

I'm sorry not to have written earlier.

That is more natural. Why? I think this is just one of those occasions when the answer is 'Because it is'.

Actually, most of us would probably say, "I'm sorry I didn't write earlier/sooner".