I don't know about the whole previous hurts thing, but Max was definitely in love with Jackie, but seemingly too straight laced to live her lifestyle. I think it was a classic case of, "I could spend the rest of my life with this person,
if
"
Max loved her. And she loved him. And he had to break both her heart and his, because he just
wasn't
that guy. And he needed some time to compose himself.

Pidder Padder? Make my Heart go Boom Bap and Then We'll Talk!

That moment is so profound, that he walks away from the window with his back turned to the viewer (or someone who could walk into his office) and starts to cry.

I think you are exactly right. He realized that Jackie was probably his last chance for love and he was never going to see her again. That had to be a moment too profound, to just go back to work.

Maybe he loved Jackie so much that he couldn't act on it because of previous hurts. Then he realized he wouldn't see her anymore and went after her but went too slowly.