The reality is some providers are doing this as a means to an end. They want to get out of this business and are smart about it. Invest in a small nail salon or to open an beauty salon. Find a decent guy that treats them right and get married.
The other reality is some providers if they like the work and like the cash they make. Have zero issues with blowing thousands on drugs, drinking and gambling. They feel completely free to do what they want when they want. They can travel around the world and make serious very money too. For them the idea of getting married isn't as much fun as you (Mr I'll Save Them) think. Not to say they don't like a reliable guy they can call and that will help them or take care of them from time to time. But playing house wife and being trapped in a 2 bedroom house in the burbs living on a $60,000/year pre-tax salary and just being normal isn't really their thing. Especially if the guy only thinks of them as a sex toy.
I am not saying it can't end well but understand which kind of lady you're dealing with first. I would highly recommend let them be who they are. If she want to drink a bottle of vodka and find some blow at 4 AM, let her do her thing. Act like you're really cool with it. If she is trying to catch you and feels you're don't approve of it, she will stop or hide it from you. That doesn't mean 4 years into marriage she is going to stop her destructive habits. Offer to take her to A/C, or to party, or to go shopping. If she is happy with a knock-off handbag and doesn't drink more than a few glasses of wine and doesn't gamble. You might have a potential keeper. If she is a party gal, have fun with her and they can be a whole lot of fun! Just don't marry her or knock her up.