I think we're dealing with a "Mars/Venus" thing here. Many of us guys have convinced ourselves that getting our butts kicked in front of your girlfriends and/or other girls would be the end of the world and the end of our manhood. Judging by my own experience and by these answers, most girls/women just don't see it that way. Lucky for us, they are much more forgiving and much more interested in helping us feel better after something like that. They're not out to emasculate us. They like us.
There are SOME very few chicks out there that are shallow enough to dump a guy if he gets beat up. However, even those girls usually do things like that in casual relationships. When it comes to girls who are really in love with a guy, I would bet that the likelihood that she'd leave him because he got beaten up in front of her (and yes, even by a smaller guy) is virtually non-existent. If she lost respect for him, it probably wouldn't be for long.
Give the ladies some credit. They're not a bunch of water buffalo waiting for the alpha buck to mate with them. Am I right, ladies?