When you have a crush on someone, you just want to be with them
no matter what.
When you love someone, you'll just want them to be happy no matter
what. When they're happy, you're happy.
A monk (yes, a monk) actually once said...if you really love your
girlfriend/wife, you'll be happy for her if she runs away with your
best friend, provided that you're sure your best friend can give
her more happiness than you can of course. That's because her
happiness is what matters.
How many people can do that?