Answer:
Yes, if you treat the person right that you are with and really love them, you will both be ok in the end!
I don't believe that we can prevent a heartbreak. I in my own experience can without a doubt say it. I treated the man I loved with all the respect and love I had and treated him like a king according to his words and still he broke my heart and left me for another woman. So I don't think that we can ever be sure because love is unpredictable and feelings change and we have no control over it!