I rarely smoked in the house. When I got my first PV, I asked my husband, "It's okay to use this in the house, since it's not really smoking, right?" (i.e., kinda asked permission; kinda said I was going to do it anyway.) He just gave me a look, and said "we'll see how it goes." That was nearly 6 months ago.
He doesn't mind the smell of vapor, and really enjoys that I don't take "intermissions" when we're watching TV or movies any more. He's happier with me taking a drag or two in his truck, instead of waiting outside restaurants or stores for me to smoke.
Actually feeling like he really supported my switch to PVs took a while, though. I think he was under the impression that this would be as effective as the other times I tried to quit smoking -- I'd be excited for several days, then turn into the spawn of the devil, then go back to smoking. With that in mind, as I kept buying more accessories, juices, etc., he thought it was a big waste of money.
About a month and a half into it, I finally sat down with him, and said, "Look, baby, I haven't smoked in over a month. That's the longest I've gone without a cigarette since I was 15. I know you're concerned about the cost, but I've added it up, and the cost is still less than half of what I was spending on cigarettes. This is important to me. I feel really good about this, and I'm proud of myself, and I want you to feel good about this and be proud of me, too." Since then, he's been 100% supportive and encouraging. I think it helps that I've converted my 3 smoking friends, too.
My mom, on the other hand, is always asking when I'm going to "quit completely." No matter how often I tell her that I'm doing awesome having been smoke free for almost 6 months, and that I'm starting to cut back on the nicotine levels, she's still really bothered by my "addiction." It won't matter how often I compare my nic addiction to her caffeine addiction, or when I finally get to 0 nicotine. She is always going to have a negative gut reaction to the idea of the physical behavior of "smoking." Big picture -- that's her hangup, not mine, and I'm going to continue to feel awesome about my new habit.
Your girl may not ever be totally comfortable with your vaping, and that's okay. Eventually, y'all will find some middle ground. In the meantime, be proud of what you've accomplished!