This lifestyle is NOT for everyone. It is not for MOST really.
There is many women that will say NO and they mean it. Just like in the Lifestyle. No means NO....
First and best thing to do is to talk to her about it. Yes, she is saying No. Listen to her. Why is she saying no? It may not be for her and you will just have to respect that.
After all, she is more important to you then you getting some strange once in a while.
I do find it interesting that you are listed as a single male but asking questions about your wife.