Spousal hire for girlfriend in US university I got a tenure-track academic offer in the US.

I am wondering how common/likely is to get the University to do a non-academic spousal hire for my girlfriend.
All the documents provided by my institution use the word "partner" which seems to suggest that it is not needed to be married.

Do you think that being married is typically an (unwritten) necessary condition?

Do you think that asking for help for finding a job for my girlfriend is only possible during negotiation, or I could potentially ask for this later?

Do you think it is possible, instead of getting a position for my girlfriend, getting a graduate school position for her?

If in the future we will break up, could this potentially affect my reputation with the department?

I guess most of these questions have an "official" answer and a "in reality" answer, but I would like to hear other people's opinion.
I am wondering how common/likely is to get the University to do a non-academic spousal hire for my girlfriend. All the documents provided by my institution use the word "partner" which seems to suggest that it is not needed to be married.
  Do you think that being married is typically an (unwritten) necessary condition?


Only your institution will know for sure, but it certainly does not seem unreasonable to ask. Given the wording I would be cautiously optimistic. However, visa might be a problem (as Herman mentions in a comment). The university maybe does not care much about your relationship status when finding a position for your partner, but they may care about having to sponsor a visa (this costs additional money).


  Do you think that asking for help for finding a job for my girlfriend is only possible during negotiation, or I could potentially ask for this later?


You should get all discussions about benefits (and spousal hire is a pretty major one) out of the way during negotiation.


  Do you think it is possible, instead of getting a position for my girlfriend, getting a graduate school position for her?


Assuming your girlfriend is reasonably qualified finding a graduate school position is probably easier than a regular job. However, an additional challenge may be if she would like to attend graduate school in your own department - then conflict of interest rules may kick in.


  If in the future we will break up, could this potentially affect my reputation with the department?


Unless "in the future" is like one month after coming to the US, I doubt that the department will care very much.