Hamster, I think she can be against it without being 100% against it. If she were 100% against it, I highly doubt she'd be in this relationship or would tolerate any sort of compromise on his usage.

I do agree with other posters, though, that the main issue isn't his usage -- it's the lying that comes with it. To me, that would bother me far, far more than him using. That's just a break down of all things essential for a healthy relationship -- trust, communication, and respect. He doesn't respect her enough to be honest with her and tell the truth. He never should have agreed to the compromise if he knew he wouldn't be able to stick to it. Then she could have made the choice if she wanted to stay or not with all the facts, rather than add insult to injury later on by lying.

JMT, you could try having another conversation with him about it, but I'd be wary of believing what he says.

I hope whatever happens, you will be happy in the long run.