Re: Funny question.
Your girl friend is dead on. What you wear and how you wear it is 75% of the battle.
When I was teaching the Observation & Perception class to the my Dept.s academy, I would wear a pair of navy blue (read that dark) pleated slacks and a plaid sport shirt. In that getup I had 9 or 10 firearms and at least that many edge weapons. I've only had 1 weapon spoted, and that was by a female. The firearms were, gp100 3", GP100 4", 2 Glock 19, Glock 26, S&W940, Jenning 22, Kel-tec 32, Hi-Standard derringer, NAA 22.
Dark clothing conceals better than light. Stripes and plaids break up bulges better than solid colors. Use your body size and shape to your advantage. Also remember that 98% of the people are not looking for bulges.
There are 2 ways to carry concealed.
1 My weapon is concealed, but everybody in the know, knows that I'm carrying.
2 My weapon is concealed, and only I know it.
If you are serious about carrying concealed, something has to change. Either you need looser clothing or smaller weapon. You can't wear tight jeans and a form fitting polo shirt and expect to conceal a full size pistol, without some sort of over garment.
Dress to fit the situation. Blend in. Don't wear sport coat and slacks to a farm fest, or overalls to the symphony.
Guns are like Jello, there is always room for more!