Yes, this has been asked, like, A LOT!!!
But once again, here's the answer:
The popular rumor is that it's about the biological mother of Dexter's teenage (now nearly adult) daughter. Rumor has it she died in a car crash. These are the only consistencies in the rumors. Whether this woman was his girlfriend, fiancée, or even wife has varied.
This is nothing more than rumor at this point in time and should be regarded as such. Since Dexter doesn't like to talk about the song's subject matter, it would be a good show of respect to not speculate on what it's actually about and instead give it your own personal meaning.
"I have tasted you Minnesota, and Minnesota you are tasty."
1997.10.11 - St Paul, MN [Roy Wilkins Auditorium]
1998.12.01 - Minneapolis, MN [First Ave.]
1999.05.30 - Somerset, WI [Float Rite Park]
2000.11.29 - St. Paul, MN [Roy Wilkins Auditorium]
2004.05.11 - Minneapolis, MN [First Ave.]
2005.07.24 - Minneapolis, MN [HHH Metrodome]
2009.06.19 - St. Paul, MN [Roy Wilkins Auditorium]
2010.07.05 - St. Paul, MN [Harriet Island]