To most guys height really doesn't matter, but to many girls it does. You just need to show your guy that you like and that height is no biggie for you. Once he feels reassured that it doesn't matter to you, you guys should be fine. Hope you two work. It would be unfortunate for 4 cm to prevent people for forming a relationshape
For the majority of women I have met height does matter. They want their partner to be significant taller then them so they can where heels. However if it doesn't bother you or doesn't bother him than that is a great feeling. The only thing that matters in love is what is on the inside. Beauty comes from within.
You're already dating him. If height mattered "that much" you probably wouldn't of dated him in the first place. So it obviously isn't a big issue for you, and that's great. Keep dating him unless what other people are saying about guys needing to be the taller ones actually means that much to you. Don't lead the poor guy on.