Its just a conversational moderation of the language.
He/she could just as easily have said「 いろいろな事情があります、ね」
ありまして would typically be followed by some clause, or phrase (since sentences don't normally end with a verb in ～て form).
So in the sentence in the original post, the speaker has just left the second part unsaid, and the listener (and reader) is left to imagine what he/she was implying.
The meaning wouldn't be significantly changed if the sentence read 「いろいろな事情がありますね」but it would sound slightly more abrupt, and slightly more definitive.