If I may play devil's advocate?
How do we know his girlfriend doesn't have a serious clinical fear of sharp objects? I had a severe fear of heights for a good many years and I still haven't gotten completely over it; any height over about 15 feet makes me nervous still.
How do we know she wasn't attacked with a knife or in an accident with one and hasn't been the same since?
How do we know she wasn't raised in a sheltered environment by someone who had a deep resentment of knives?
Is it possible she's not a control freak but just has a problem with this one thing?
The fact is that for every one of us on bladeforums who loves knives there's someone else who feels differently about knives.
And let's face it. A number of us live and work in an environment where we ignore hoplophobia at our own peril. Some of us have a loved one who is adverse to knives. My mother for instance took years to let up on me and I've actually finally bought a little Spyderco for her. It's a real problem and maybe it's not fair but it's not going away.
My suggestion is to do what I do: yes I carry a good sharp tactical folder everywhere I go. Two more often than not. But I also carry two SAKs and a multitool and all sorts of other little gadgets.
I'm not afraid to use them either. I use my Leatherman and SAK daily and not just for myself. Fairly often someone asks me to tighten or fix something. Everyone wins. I get to carry my toys, I can be prepared, and on those occassions when I do whip out a knife, well it's okay because I'm the "knife guy". Of course I work in a highly sensitive environment so I have to be extra careful and most people probably wouldn't encounter the level of knife resentment I do.
But I'd say take a similar approach with her. I'd keep your new knife and carry it with your old one concealed for a while at least. It will appease her and get her used to the idea that's part of who you are in time. If you are really brave and she's not an extreme case, I find a lot of people (and not just the ladies) who are ignorant of or adverse to knives can be persuaded to lessen their opinion by a gift of something useful, colorful, small, and benign like a Leatherman Micra or Juice, especially if they've never had something like that before because they will suddenly find they're using it every day.
I see where you're coming from. I am curious about the knife in question though as it seems interesting in its own right: Is this "SWAT" knife a Smith and Wesson product? What model are we talking about here?