Sho Ishizaki

Joint car insurance policy? Joint cell phone account? Affidavit of your father stating you both live there...  Suspect obviously there wouldn't be much more available as in medical coverages/life insurance policies and such with both of you in school.

Maybe affidavit letters from your family and friends. And start collecting more evidence from now on so when you have the interview (probably in one year or less) you will have more stuff to add to the case. Join car insurance. Driver license showing a common address, utility bills under both names of the AOS's beneficiary name, etc. 

A copy of both of your ids showing you live at the same address, is he an authorized user on your credit cards? Show bank statements that span the length of your marriage. Affidavit from your father showing he is allowing both of you to live there as well as proof he owns the house (deed), photos of you guys places and labeled.

USEM is not a difficult embassy as long as you have all the required documents and have genuine relationship.   Relax.
 
http://www.visaconnection-philippines.com/k-1-visa-application.html
 
Did your J-1 have a two year requirement for staying in in the Philippines after returning?  
 
Your fiance being at the interview can always be helpful, but truly is not necessary.   I was there with my wife, but I doubt it influenced her approval for her visa.   Just the same it was a great experience and I highly recommend it if you fiance can attend.
 
 
As a last note, make sure to get the CFO sticker in your passport after you have your visa.
 
 
Relax.   Smile and look the CO in the eyes when speaking ..     3-5 minutes later you will be done and smiling even bigger.