Hi Grumpii,
A friend of mine was doing the same thing a few years ago behind her boyfriends back. She claims she just liked male attention and the 'escape'. She reinvented herself and online chatting gave her a confidence boost.
She didn't phone anyone though.
Eventually though her, boyfriend found out. After a lot of debates, she realised how he saw this as cheating and stopped. At least she said she did, don't know for sure.
If your wife however is suggesting you see other people, that's a differeny thing altogether. Maybe she wants an open relationship or may want more attention.
Best wishes to you and I hope you sort this out and stay happy.
X.