I haven't read all the responses so I apologize if this has been covered already. You were talking about your wife being uncomfortable with you looking for a relationship on a dating site. I had similar insecurities and it took me a long time to articulate why that is.
Dating sites are a lot like shopping for a partner. It seems that pretty much anyone who responds will do. It made me feel like *I* wasn't really worth anything since anyone who came along and responded to an e-mail would fill the role of "girlfriend". It made me wonder if I was just in the position of "wife" because I happened to be there.
I have no idea if this is what is going on for her but it is worth asking. I know a lot of people meet on line these days. There isn't anything actually wrong with it but if it is triggering something in her there may be some kind of underlying reason why.
Everything will be ok in the end. If it's not ok it's not the end.