Trust your instincts: get her out of your house, your lives, ASAP.
She is a train wreck waiting to happen. You can see that coming, she has set herself up for it -- gumawa ka ng paraan para hindi ka maging collateral damage ng train wreck nya.
She is 19, very aware of her sexuality & how far she can wield it -- she has put her conscience/morals (if any) in the freezer -- nag research na nga how to nego with her kakabitan, when she agrees to be a kab1tch. Susko. Instead of employment search, kabit search gawa ng babaeng ito. Hindi yan bata, see her for what she is: a woman who is obsessed with getting a comfy life the easy way: as a parasite, regardless of who gets hurt. Alam nya may masa saktan sa balak nyang pagkakabit -- but she doesn't care. All she is focusing on now is how to get the best deal/best benefits. Kaya nya inayawan your BIL, and her amo in the province: assessment nya kulang sa funds to keep a kab1tch financially comfy. And, sa statement nya sa yo about not being your hubby's kab1tch: Aba, Aba, Aba -- na assess nya rin financially your hubby. And, na assess nya may kab1tch your hubby, it just isn't her. (How disrespectful to you, the hand that feeds her -- to say such out loud, warranted or not the cheap remark may be.)
Sit her down 1 time for a serious talk.
TELL HER:
1. Challenging enough being a wife, harder to be a kab1tch. Men stick to the wives they complain of, but change kab1tches they go crazy over (for some time). She should aim to be a wife, not a kab1tch. Tell her not to price herself low/cheaply. Think of her future kids/bastards.
2. Sa dami dami ng teleserye about wives & kab1tches -- the Winning Exit Line lies best in being financially self-empowered. No man can give you insurance. The best insurance is to provide for yourself, and to take care of yourself.
3. Raise her ambition. Hwag basta kumabit lang. Go abroad & advance herself. Make her see that if she upgrades herself, she levels up to the type of men she can consider. Or, kung decedido maging kab1tch, hindi lang seaman. Haynaku
Then, show her the door. I am all for helping -- but self preservation comes first. Sometimes, it does not help to be concerned about someone who is out to put herself in harm's way & has no guilt about wrecking others' lives -- even yours. Really. Sooner or later, she will pay the price for her lack of morals now. Why risk co-paying the price for her lack of morals? Just saying.
IF she is willing to go work abroad, sure - help her financially. But do not let her into your premises again.
Snakes are best kept out. She is one, if given the opportunity.
Get her out of your home ASAP.