This is a tough situation Amy. You are going to need to ask for something or else you will continue to feel like a pushover. Since they know you are a getting less than others, they should expect it. You might not actually get more money but they should respect you more if you stand up for yourself and you will be sending a message that you are not to be ignored. If they say they just can't afford to pay you more, tell them you can accept that if they show you financials that justify what they are saying. I've seen that work before, it can show you are interested in the health of the company as a whole and not just your world. If in the end they don't offer you more money, you can make a decision to stay or go knowing that you tried. If you decide you are willing to go, you can line up something else (easier said than done, but still) and maybe give them a last chance. Then you will really know the most they are willing to do.