I am ready for all the 'there are no secrets in our relationship' but surly there must be something your other half doesn't know?
For example, mine doesn't know that I had an affair when I was married to my ex husband with a man who is quite well known in football.
I'm not proud of what I did, but I was 21 at the time, in an abusive relationship and flattered that this older man complimented me and showed an interest in me. It was the first and last time I was unfaithful and definitely not something I can see myself doing now I am older and a little wiser and in a healthy and happy relationship.