Location accuracy uses (from best to worst) gps, wifi, and cellular triangulation. Your question would take a lot of text and links to completely answer so I'm just going to try and give it a high-level approach.
Many things have to happen correctly for your husband to get your exact location: you need to have a clear signal from the gps satellite, the cell signal on your iPhone needs to be good with a low latency (delay) sending your coordinates, and if the gps signal isn't very good but there's wifi available to you, the wifi location lookups need to happen quickly (again, over the cell signal). Now, if you move, this entire thing needs to start all over again.
Cell signals can only triangulate your approximate location between the 3 cell towers. They can't get an exact location, like a gps signal. If the cell towers are miles apart, like they usually are, it can report your location as far away from where you actually are. If the cell signal is bad, it's guessing at your location (based on where you were in that triangle) from the last time it 'saw' you.
Like I said, this is very high-level and it's very easy to go into more detail (and really confuse you!) with a simple Google search. Why it didn't report your exact location when you were at home, with wifi, I'm not sure. Maybe it did report your exact location but your husband's cell or wifi signal was poor so he was sent a 'guess' based on the last time his iPhone saw your iPhone.
It's very difficult to troubleshoot these types of issues online. If you notice this type of inaccuracy happening more often, it could be indicative of a deeper problem with your iPhone so a trip to Apple might help solve the problem.