I agree with Zoso, it may be a good time to get some legal advice on what your rights are and are not. It is often hard to evict someone who has established living in your home, whether renting or co-existing. Only your lawyer can tell you how this applies where you live.
Knowing your choices, then setting a plan in place, will empower you more than you know, whether you follow through as planned or decide to take another route.
Good luck, you deserve better than active addiction in your home.