Becoming one flesh means taking care of my wife the way I would take care of myself.
It only makes sense.
What person doesn't seek food when hungry or water when thirsty?
That same level of attentiveness and concern should be displayed for my wife.
Always aware of her wants and needs and making them a priority in my life.
Beyond it being a ministry to my wife, it also serves my long-term best interests as Paul points out here.
My wife and I are one.
Spending myself to love my wife is an investment in my marriage's long-term success and my satisfaction in being part of it.
Our lives are measured not by how much we have accumulated, but how much we have given away.