I feel your pain (no seriously, not like Bill Clinton). My wife even to this day will not let me take out my friends in the presence of her. She acknowledges that while she does not like guns, she respects me having them and she really appreciates the extra security.
That being said, before my significant other became my Wife, I told her outright that I don't drink (to excess
), do drugs, smoke, or have any other hobby other than collecting guns: Basically, I told her if me owning guns (and having 3 safes later) was a problem with her, then we would have to really reconsider if she trusted me at all.
I went through all of the BULLSHIT: Having a gun in the house you are 60% more likely to kill one of your family members. All of the Brady Bunch bullshit you could throw at me, and I was all I could take but scream. I then loaded Gunfacts on her laptop one day and I caught her reading it... Basically, it was an unspoken word that as long as she did not "see them" I was OK.
As a sidebar... When we were making our family trip down to Florida this year, she asked me if I was taking my "friend" along. I said "Yes, absolutely." and she stated that she was happy to hear that.
All changed when we had our first daughter, and after that she has suddenly adopted the theory of "My home is my Castle, and if you eff with us you are going out in a body bag." Kind of funny how a life changing moment turns the perspective 180 degrees when you look at a little baby.
Anyhow, I have been trying to get her to take the class and get an LTC, but I am not pushing. I work from home 99.9% of the time and she is still in the "I am now OK with all of this, but I still do not want to see them" attitude. So, at least I have won the battle of ~5 years. The best part was when my Mother-in-Law found out I had guns and wanted to know what types and calibers as she wanted me to suggest what she should get for protection!
And yea, she told my Wife to grow up and get a set and go shooting with me.
Anyhow...in your case... You my friend need a gut check... With that much pressure, I would have told your potential father-in-law to mind his own business and FOAD.
It all comes down to whether you truly LOVE your girlfriend: If there is any doubt, split and reevaluate.