Preserve those days and move on as he is taken and not only that the feeling that you are having is just a crush .And things are not as rosy as it looks after honeymoon life is as usuall taking care about family and responsibility.
And what are you trying to gain his wifes place well honey you left it and now its taken.Build a beautiful life with this man who loves you so much and have you ever though you are doing the same mistake you so unsure right now and i can't entirely blame you your age is such too.Trust me once you are settle with you BF and have your family you will not have much time to think since you will have your own little family.
Move on dear that's the best advice i would give don't do anything stupid and preseve those days as a memory they will make you laugh later.
All the best
