Why is marriage so hard?

I'm a revert I talked to multiple women with a halal intention. In the beginning it always goes really well and after a short or long time it doesn't work out. Always hamdullilah. I'm currently heart broken so I really don't want to meet someone any time soon. (She told me she doesn't want to talk to me for three months, I don't have a good feeling about that.) But why is this so difficult?