Nothing about meth cures BV. If he has it and passes the bacteria on to you, you could get it. After the last time (and I sincerely hope, with him cheating and using, that it is REALLY the last time and you never fall for his lies again), get swabbed at the doctors for all the sexually transmitted diseases and conditions. If the doctor prescribes an antibiotic, take the full run of it. And get that lying, cheating, self-indulgent jerk out of your life. I don't know you but I do know that NOBODY deserves to be with someone like that, especially in the name of so-called love.
Yes, I'm with Annie - are you sure this is BV? Have you been tested? The odor after sex is an indicator of BV, but you should test.
Given that he's cheating, you really do need to test for all STDs.
Are you in therapy? I hope you are. What you're going through sounds really painful, and I hope you can get to a point where you no longer say yes to having sex with him. I'm sure he's a very troubled soul, but you deserve better than to put your health at risk.
Hugs to you.