Be upfront with your current CEO. Tell her that you've received an offer that pays good money, and you'd be working with people you already know and get along w

Be upfront with your current CEO. Tell her that you've received an offer that pays good money, and you'd be working with people you already know and get along with very well, so you would be a great fit in that team. Try not to burn bridges though. Oh, and if you're going with the job offer you got (and you should), don't offer to "help out" for the current job a few hours a week. They'll still have expectations from you to work more than you can.