I'm a married man looking for an apartment to live with my wife from February 2014 until April 2014. How can I find an apartment for this time period?
If you don't speak German, Airbnb is your best bet. For the period you mention, they feature some 150 entire apartments that are suitable for 2 persons.
If you are searching for an unfurnished apartment, this is the most popular site in Germany:
Otherwise, you can check Craigslist Munich for apartment listings, almost all of which are furnished. Alternately run a simple search on Google for "Furnished apartments Munich" and you will see lots of different companies providing basically the same service.
Edit: I misread the original question, the OP is only staying for a very short amount of time. My advice is best suited for people staying over a year.
I would also recommend HouseTrip.com. We used it to find apartments in Budapest, Prague and Vienna and had a great experience overall! I was impressed by how flexible the search feature was (i.e., we were able to search for centrally located apartments that can sleep 6 people and that include WiFi and laundry).