I simply did things like leave my ring off and at home on a Friday or a Saturday evening when I went out and met my (male) friends for beers and a cigar. When it got back to me thru our daughters that their mother thought I was with someone, I just smiled and said "I'd never do that -- that's not right," and left it at that. Same when my wife would ask or accuse me.
I never lied. But if by suddenly wearing some new clothes or some new cologne leaves her with the impression that someone else is interested in me, I didn't do anything to squelch that belief.
