This is not an equation, it's just a long math line. I want to break it into lines with right alignment. I tried several solutions including align, multline, but somehow I can't get it to work properly. It always forces the text to center. If I use equation + split, it still force the text center. Is there a way to get rid of the centering property? Thank you.
Minimal example
\documentclass{article}
\usepackage{mathtools}
\setlength{\parindent}{0pt}
\setlength{\parskip}{1ex}
\begin{document}
$X \times Y = \{$
$\{a, b\}, \{a, c\}, \{a, e\}, \{a, f\},$ \\
$\{b, b\}, \{b, c\}, \{b, e\}, \{b, f\},$ \\
$\{c, b\}, \{c, c\}, \{c, e\}, \{c, f\},$ \\
$\{d, b\}, \{d, c\}, \{d, e\}, \{d, f\} \}$
\end{document}
Edit (according to Stefan Kottwitz's solution)

