Spanking your wife/girlfriend is a fun way to communicate dominance (e.g. alpha or lover value) without hurting comfort (e.g. beta or provider value). While many or most of the ways to communicate dominance involve openly stated demonstrations of your higher value (or dark game demonstrations of her lower value) this is on the surface just a sexy game. However, routinely spanking your wife sends her a strong unstated message of dominance, even if the spanking is just a game.
With time your wife will get used to more and more spanking and since her hind-brain will see her husband as her ‘spanker’ she will see her husband as more alpha. Since her husband is more alpha she will be more happy and satisfied compared with non spanked wives.
(hmm, yes, I spank my wife.)