This "keeping score" thing is disturbing. All the more because in the past I have done it.
You have to let each of the four relationships in this group (you and your wife, your wife and Nikki, you and Nikki, and the three of you) develop as they need to. You have to stop second-guessing the others, too - and you have to establish the dynamic that if someone is uncomfortable with something they will tell you and then the three of you can work to resolve whatever is disturbing. For example "It makes me uncomfortable when I see you two french kiss" doesn't necessarily mean you stop french kissing, but you do it in private.
It's too easy to get into a dance of doing what you think others want you to do, and crippling yourself and your relationships in the process. If you're not sure about something, then get into the habit of asking.
"Listen, or your tongue will make you deaf." - Native American Proverb