Unfortunately for Regina, there aren’t many folks around, (in Storybrooke or FTL) who are in her league. If there’s a problem that’s beyond her means, her only superior is Rumple/Mr Gold, (and also Blue Fairy, but she’s hardly gonna help the likes of Regina). So even though he can play her like a fiddle and screw her over without breaking a sweat, she doesn’t really have any other option than to deal with him. Sucks to be her.