If your significant other is a woman (can't tell from your name/post, but I'm assuming!), there really is a tremendous amount of options coming out on the market. It might pay for you to both do a little research even before you shop. These models (discussed in articles below) may or may not fit her needs... but I think you can glean from the articles what some of the common features of these ladies' shotguns are....
Compared to the "average man" that most shotguns are actually designed for, the average woman will have shorter arms, shorter fingers, a longer neck, and be far more likely to have cross-dominant vision. So, a lot of these guns have features to account for all of that (and the more expensive ones seem to be highly adjustable to get more of a customized fit). Happy shopping!
http://dailycaller.com/2014/10/02/welcome-to-the-golden-age-of-shotguns-for-women/3/
http://www.shootingindustry.com/women-continue-to-benefit-from-shotguns-designed-just-for-them/
http://www.range365.com/six-new-shotguns-for-women
BTW, if you didn't know, there are also NJGF "shotgun shootouts" held several times a year at the Clinton, NJ Wildlife Mgmt Area - would be a good opportunity for her to handle different shotguns and get an idea of what features she likes. I don't think there were any specific ladies models at the last one, but there were plenty of 20 gauge models... and someone had a youth model as well (another option, depending on your SO's size) that featured a shorter distance to the trigger, good for a small-framed shooter.
Edit: let me clarify... I'm a total newbie myself! Only shot a shotgun ONCE. So, I profess no expertise. But I am, however, a world-class googler! LOL.