Why Do Relationships Have To Be So Difficult?

I don't know why relationships have to be so darned hard. We grow up having this idea in our heads that we are gonna be with the partner of our dreams, have children, the cute little house on the corner and then bam! something seems to go wrong and I just don't get it. Why is there so much heartache when it's supposed to be nothing but bliss? I guess our society has us to believe that getting married is what we are destined to do and we go into it with our heads sunk into our hearts......and then, when the honeymoon's over it's just back to business : work, children, bills, life....just everything. Do we lose that "honeymoon" phase due to the basics of life? So that also raises the question: do we not look for a partner that we can stay with forever when wer'e looking or do we settle for something less because our heart has fallen head over heels? I don't know the answers here but wished I did. I felt like I got married when I should have waited, but my heart was enamored with him. I fell hard and it felt good. We had an amazing love which I felt lasted for awhile but at some point, he made the choice to cheat on me, leaving my whole world upside down. I don't know what my future brings because I am wondering if I am going to go down the same path again....maybe not with someone who cheats on me, but someone who hurts me in other ways. Is it safe to fall in love again? I think maybe so, but perhaps this time with a little more "wait and see" type attitude. Why does love have to be so difficult?