Frankly saying, This game equally distributed into two halfs for lewd content for wife. And, for other girls, no ntr. But still, those scenes can be enjoyed by all type of fans as it is a totally different route. Wife scenes (ntr or non ntr) can only occur if u select kat options everytime. If u select other girls options, you wont see wife that often. Don't worry, She won't cheat on MC whatever route u take.
So, yeah, in a way, this game is 50-50 as far as wife is concerned. But i'm giving you guarantee, that you wont regret playing this game for kat(wife). You wont see that much caring, loving, loyal wife even in strict monogamy games. She always put husband's needs first.