I am not a native speaker, but most of them have gone to bed. I can correct your grammar, but I'm not sure whether the phrase itself is the best choice of words. I think so, though. Vous brisez mon coeur.
On second thought, if you know each other well enough to be heartbroken, the tu form may be more suitable: Tu brises mon coeur. Tu is less formal.
On second thought, these might be better:
Vous me brisez le coeur
Tu me brises le coeur
Thank you so much!
I have not taken a french class since high school -my grandfather(deceased now) spoke fluent. He is not here to help now. My boyfriend was born and raised in France - when ever he does something that displeases me I tell him he breaks my heart. Wanted to say it in french. So I am not so good in the grammer! I am just trying to learn by myself,
So thank you again!