Platonic relationships are tricky.
Usually, it is the guy who has unrequited feelings, and often can ruin things.
But whichever side of the equation is tipping, you have to be very careful.
You need to be reasonably sure that your intended is likely to feel the same way - because whichever it goes, it's going to change your relationship.
Either you will proceed as a couple, you may continue as friends, but it will never be quite the same again, or it may split your friendship up.
It is easier for a woman making the move because women have the ability to see what is there, as opposed to what they would like to be there, which is what men see, and get wrong most of the time.
So, decision time.
If you don't want to lose him as a friend, then learn to live with the fact that he will see other girls as partners, and not you.
If you think you have a chance, make a move and see what happens.
A final word of caution - either he thinks you wouldn't fancy him, and he will be thrilled to find you feel the same way or, and this is the hard bit -
he hasn't made a move because he only sees you as a friend, and is comfortable with the way things are.
Good luck.