Being the commish, you really can't just say "well I think it's fair, so I'm allowing it." It's your team, so the conflict of interest is obvious. Since people have objected, I think you should put it to a vote. If your league votes it down, you really should go with their verdict. It sucks to be a commish sometimes, but that's part of being a good one, putting the league's best interest before your own. Give them a good argument for why it should go through, but live with their choice.