Whether is it Boy or Girl whoever, the human body was made up with some unexplained divine knots inside. When you born as human in this world, you will get some abilities & qualities by birth itself. For instance, before marriage you are seeing some interesting beautiful person at somewhere. You will get some spark right? Yeah, that's called crush.
Do you think after marriage you won't get this same feel if you see some other person with some different impressive quality? Not at all! You will get that spark again on someone! So marriage is not a bar for having crush! Yeah, till you die, you will get impressed by someone at somewhere for sure! It's called Harmon effects & the chemical reactions that's happening because of the visuals that you seeing which you like or dislike! So, your body was made up like that by the ultimate creator from the sky! Respect the creator's creation!
Getting crush on people will happen often because of the impression! Understand it psychologically and don't get confused with love & life commitment! When you like or love something, just think about it often. That will set you a nice mood in this hectic world! Use the nice opportunities which will make you to smile & get happy! At the same time, limits are always a best answer for any kind of relationship & desires till your border which was given to you by yourself, family or your reliable circle!