This is indeed the case. But feelings get hurt when it’s done to them. Studies are already showing that increases in female income is also correlated to increase in infidelity levels. A lot of cheating isn’t just shallowly based on lust or opportunity.
There’s psychological reasons behind it too. It’s about power for a lot of people and validation. When you contribute more, you tend to take your partner for granted, pride sets in, you feel like you running shyt so you don’t have to stay faithful to somebody who is beneath you when something better comes by.
Both male and female nature can be used to justify promiscuity. Female hypergamy, male reproductive impetus...but like you said...self-control is where you draw the line, particularly if you trying to build something.
Its just as hard for women to tamp down on their desire to fukk the next best thing or not entertain attention from other desirable dudes, as it is for men to control themselves around new p*ssy.
So given this reality, either both need to be willing to put the work in or you don’t need to be in a relationship.