This guy broke up with me for my best friend. Should I take him back?

So this guy and I had been dating for about 6 months. And we went out, and hung out a lot. But like 3 days ago he just dumped me out of the blue... FOR MY BEST FRIEND!! But then yesterday he passed a note to me in math saying 'I'm SO sorry. I really messed up, please. I love you'. Now I don't know if I should take him back. Or if he will just break my heart again. I have yet to answer, and my mom just keeps telling me, "Do what you're heart id telling you." But my hart is telling me a billion different things at once. So please help ME!!