I'm going to ask my wife to stop eating more than me
Why don't you want her to eat more than you?
I don't want her to gain excessive weight when she's pregnant
Pregnant women do need to eat more. It is good to care about her health and the baby's, but your interference is not necessary as it is unfounded.
You're not helping, I want to control her.
Trying to control your wife through her eating is not right. Let your wife make her own decisions or risk losing her for good.