This question was not very present throughout my life, the answer came a few months ago in a natural but still impactful way.
When I was younger I thought being a man was having a big body and lots of options of women, being liked by them and admired by other guys, being like an alpha male.
Today I am married, that is, monogamy, if you prefer, I also have a child. So I'm not just married, I also have a responsibility that goes beyond keeping myself alive. I live my life with a survival instinct and at the same time a strong sense of debt to these two people who are the basis of my happiness.
Being a single man is easy, basically, you need to have an occupation and not starve.
THIS IS MY MOMENT when I get home after a trip to the market and organize the food in the fridge and in the pantry. My heart fills with joy and satisfaction. It's a mix of a sense of accomplishment with genuine gratitude.
In short, for me to be a man today is to have the ability to provide. Provide food, security, good housing, and many other essential things that give a decent life to those I love and who need me.