I used to feel the same way when I was in my early twenties. Like you, I also have friends who are my age, are married and whom I feel sorry for - they are broken men too.
From my own experience, and the observations I've made on the lives of other people my age, I've learnt the following things:

1. Do not marry before 30 (read: when you're ready. 30 was just he age for me)

• I'm glad I never got married in my early and mid twenties because during that time:
  • I've really enjoyed being single: I could do whatever I want, I got a chance to travel the world, I could stay out as long as i want, I could just switch off my phone and disappear for days and no one could care, I've started two companies, and both failed, and been bankrupt and I'm now working on the third company - having the freedom to experiment with my time was an advantage my married peers didn't have.
  • The girls I thought were pretty in my early twenties are not so pretty today. There is a saying: "men age like wine; women age like cheese". Women are prettiest/sexiest in their early/mid twenties but men get more attractive the older they get. The kind of girls I could not date because they were way out of my league when I was in college are the kind of girls I'm dating now. I guess that's because I'm more confident now. Maybe it's because I'm more attractive. Or maybe we'll never really know.
  • Sex and beauty will eventually fade - you should only marry when you understand this.
  • I have changed a lot and learnt a lot about myself over the years. Some things I used to find attractive in women in my early twenties are no longer so attractive now.

1. As you get older you start to get lonelier

• Firstly, you no longer just think about what women can give you but you start thinking what you can also do for others - you start to realise that it's not just about you.
• As you get older, life experiences become less exciting when you have no one to share them with. To give an example, you can visit the best restaurant in town or go to the best club and dance all night. And have a good time but the experience will be so much richer if you share it with people you care about, people you love and people you will meet again in the future and start a conversation with the words: "Do you still remember that day when...". The evolutionary process has hardwired human beings to be social animals. I'm now getting to the age where I value the freedom to do whatever I want less than the freedom to share life experiences with someone I love.

I'm actually 29 years old and you found this perspective useful, you may also want to read about the things I have learnt about life in the last 10 years in the letter I recently wrote to my 19 year old self.