Most Helpful Guy
Marriage is not just a symbol of love and commitment between a couple (men actually don't have a problem with that part), it's also a LEGAL CONTRACT that is enforceable by the government.
The main purpose of marriage historically was to legitimize children, so that lands and titles could be passed down to the next generation. In modern western society, those concepts have been almost eliminated; we don't legally recognize bastardy anymore, in the US and other places titles have been dispensed with, and only a few wealthy families have anything significant to pass down.
And as a result of the women's movement, which was taken over by radical feminism in the 70s and 80s, marriage laws now heavily favor women at the expense of men, so many men have looked around, seen what happens to their friends who marry, and decided just to skip it. They realize they can still make a personal commitment to their girlfriend without entering into a legal business agreement with her that has terms that are very much against him.
If I had the benefits and liabilities of marriage brought together into a single contract, there's not a lawyer in the country who would recommend a man to sign that contract, because under current laws, men have far more responsibilities and liabilities than they have benefits. If the laws are ever balanced out again, you might see interest in marriage increase, but it's been steadily decreasing for the last 30 years.