What you need to do is get something that fits you---asking somebody else what gun you need is like asking them which girl you should marry; they're not you, so they don't know.
You need to be able to comfortably and easily reach all controls without having to contort your hand in fifty different directions. Pick the gun up, get it in shooting position and then squeeze it hard for ten seconds. If there are corners, contours or sharp spots that bother your hand, they're going to bother you when you're shooting it. Keep it clean and oiled. Yes, revolvers are reliable and don't rely on recoil or gas pressure to function so they can have some advantage for a beginner, but a good quality auto--clean and lubricated, shooting good quality ammunition--is a reliable firearm. And yes, a revolver is simpler to learn, but we're not talking addition/subtraction versus calculus here. The VAST majority of military and LEOs arrive with little or no firearms experience, and have learned to use 1911s, Beretta 92s, Smith and Wesson 3rd Gens and a host of other pistols just fine, and in not all that long a time.
Am I arguing against a revolver? No--I have many, many, many and I love them. But buy it if it fits you and YOU are comfortable with it, not because a guru told you to.
As to caliber--the biggest you can shoot well is a general rule of thumb, so stick to it. If a 9mm is your limit, then stick to it, as a 9mm shot well beats the holy hell out of a 357 shot poorly. Bullet size doesn't necessarily reflect shooter comfort, either. Until you get up to 44 magnum and above (or 357s in EXTREMELY lightweight snub-nose revolvers), almost nobody is actually recoil sensitive even though they think they are. Noise/concussion cause people to flinch far more than kick. As such, many will shoot 45 ACP better than 40 S&W, even though in many cases the recoil energy is almost identical. The difference is, the 45 usually isn't breaking the sound barrier, where about half of factory 40 loads are. Sonic boom as soon as it leaves the barrel means more noise, and people start flinching.
I also agree that, if you're not going to carry it, a long gun can be a more effective choice that a handgun anyway, as the learning curve is a bit less sharp (they're inherently easier to learn to use because more of you body is able to help you control them) and you can get into an excellent one like Remington's 870 shotguns or the Browning BPS for much less money than an equivalent-quality handgun.
Last two points:
1)Practice. Twice a year is not practicing--you need to know the gun's function intuitively, you need to be able to get on target with it quickly, and if you have a malfunction you need to be able to clear it in a second.
2)The creeped out girlfriend has to be fixed---if it's going to be in the house, then everything I've mentioned above has to be as true for her as for you. She'll achieve confidence through correct exposure. Get professional instruction--many ranges offer classes taught by certified range masters, so utilize them; a $200 expense that teaches you to do something for a lifetime isn't all that steep. Shooting is no different than sky diving, scuba diving, or driving a car---all activities that are dangerous if done incorrectly, but also activities that damned near any ten year old can master if instructed by someone competent.
Best of luck.
