Dear NT:

You wrote:
> “With him, solitude was very difficult.”
>
> Does this sentence mean:
>
> 1-It was difficult to be alone with him.
> or:
> 2-It was difficult for him to be alone.
>
This would be a very uncommon construction in English. It would have to mean #2, because solitude means “being alone.” If someone else were with him, he would no longer be in solitude!

The sentences #1 and #2 are much clearer. Stick with them.