You only have a right to make changes in yourself. You CAN ask your partner to make changes for you-but it's EASY for that to become a manipulation instead of them actually having the CHOICE (meaning they can say yes OR no without "punishment").
SO-I advice breaking it off with your secondary on the basis that it's not working out to be part of the quad.
BASED upon your options.
If it were me, I would sit down and lay out some VERY specific personal boundaries and then sit down as a group of 4 and explain them. INCLUDING the necessity for
A) an agreement on whose time is whose and when
B) that if anyone creates drama over that time-they are out of the quad.
Shrug. It's really a matter of you deciding what it's going to take for you to be the best version of yourself AND THEN upholding those boundaries in terms of your lovers.
You don't have a say-so with your metamour and how they behave in the duo of THEIR relationship(s). Only in terms of how you are treated.
IF they are being violent and out of control with a lover-that lover can set boundaries-if they don't chose to-you can decide if you are comfortable dating someone is ok with being abused. But-you can't MAKE THEM leave an abusive situation.
She isn't talking about a lover of hers-but you might consider reading gagagirls blog regarding her friend in an abusive relationship and how she's managing to be supportive but NOT overstep boundaries.
"Love As Thou Wilt"