To make it clear, either marriage or having children can not be a must because everyone do have all rights to decide if they need a partner or an offspring of themselves.

A man and woman a needs companionship to spice their custodial life experiences. It is usually required a duo partnership with the characteristics of both sex lifestyles being matched with the ability of both parties to learn tolerance while diligently chasing one goal but failure to stick to understanding is why marriages are broken (divorced).
That categorically states that marriage is not a "Do or Die" affair. Of course if you tried to pair in some occasions and it does not work out good for you, just leave else, the lifetime marital entitlement would be unfair and potential to ruin your life.
Don't be in an entangled relationship just because you want to earn the title "married".

My advice to you OP is that... You should try and whole heartedly bring out your mind to give this a try because, if everyone thinks like being single and no bearing of children, the world will be empty somedays you would not have even existence if your parents never conceived you to live.

I also understand the irritation accompanied with some individuals which of you find yourself in a relationship with one may refer to a ruin (messy) of your life but on the other hand in marriage, you don't just get 100% of partner you may ever wished for neither are you portraying a perfect person of whom your partner may desire for life.
On that reason, maturity and tolerance should be the primary exhibit of both parties before any of perspective is considered.

Therefore, having married and having children is necessary but not compulsory.