Someone to talk to. Take this for what it worth. My wife was sneaking out to a guys apartment wile I was at work. Long story short. She gave me the same answers you got at first.then when I got her to break down and admit she was sneaking out, see still insisted nothing happened. Yea ,she just planed and waited for me to go to work then hatch her plan.only went on for 3days.(she says) never really found out what happened in that guys apartment, but you don't sneak and plan like that for doing a good thing. Bottom line, I stayed with her. That was 10 years into our marriage. It's been 20 years now and each and every year I'm reminded because of Christmas, (long story) and it digs at me worse every year. Think about that. The happiness of the rest of your life is hanging in the balance. Looking back, I should have walked out.(a lot of reasons I didn't) We can forgive the people we love but forgetting really never happens. Good luck on what ever you decide. Like I said take it for what it's worth.