The problem with sex is - we are all supposed to conform to some kind of mythicl sterotype who are at it all the hours they ar conscious, and anything less is a huige failure.
A couple is made of two individuals, so that's twice the unique input into a relationship.
As to how often is 'enough' - it's what's enough for the two of you, which may be once a year or twice a day. What you shouldn't do is get hung up on comparisons with other people, because they are meaningless - none of the parties involved are you or your wife so any camparison is utterly pointless.
If you two feel you have an issue, discuss it, and work it out between yourselves, and don't tell anyone.
I would never discuss my sex life on a forum like this - it leads to helpful advice from strangers which is meaningless because there are no set 'rules' to adhere to, or deviate from.
Work out what suits both of you, and then don't tell anyone - that's the recipe for a happy marriage.