Jon,
I don’t know what it is that your wife “gave up” when she married you. Polyamory isn’t about sex. It is about loving and caring for more than one person. I have no friggin’ clue where your wife is coming from, and honestly, her participation here might be a help to you. So, not knowing where she is coming from, I’m going to tell you where I’m coming from. Fortunately, I wrote this all down before, so let me go find it. Ok, I post too much here, but I found it. Here is the link.
What Brings People to Poly
Read it then you will know where I’m coming from. What did your wife give up when she married you? Did she just give up having multiple sex partners? Or did she have people in her life that she loved and cared about that she had to ignore those feelings about because she was now married? If it was her personal attachments, that is a poly issue. If it was just having sex with others, then that is a swinging issue, and one that you two need to come to grips with together openly and honestly. Good luck and we will be here to support you as much as we can.
S