Marriage regulates the legal environment for partnerships. Who has what right for the children, who has a right to make medical decisions in the name of the other, how are the finances regulated, etc. and that is important because it makes life easier. If your parents are dead you may want your partner to be allowed to e. G. Make medical decisions for you, when you are not longer able to. Taxes are a good reason, because they might enable you to take better care of your children. The legal net for children is a good reason, because they might profit (from your point of view) from that closed form of relationship.
But it is legally nor socially necessary to get married to have children, have sex, be and live together. You can practice your love to the full extend without getting married. Therefore love is no good reason to get married.
When you choose to marry someone you LOVE them and it's for that reason that you are marrying them. Other good reasons to marry can be that you care about them and that you have a lot in common. You enjoy each other's company and you can see yourself having kids with this person one day. If you don't feel any of that towards the other person than you should probably wait.
Call me a sappy romantic, but I think love is one of the best reasons to get married. In the past women were forced or pressured to get married because they had no way to be financially independent. Now that women are educated and self sufficient marriage is becoming a symbol of a couples love and committment to one another.
Yes, there is all that legal ramification for marriage, but a partnership that would be worthy of establishing a marriage honestly works much better when there is love. Overall in the world, marriages formed of love are generally more satisfying than ones arranged for profit. And vice versa: Marriage is nearly necessary in modern society to handle the fruits of love, namely children. Without marriage, the benefits for a child here in the US are much less.