How to give him spave

I have been with my boyfriend for 3 years now. We're soon to be engaged and he is the love of my life! I'm very clingy and I don't know why. We have talked about that and hea admitted he doesn't have a problem with that. But today he expressed to me that I don't give him enough space. Any suggestions on how I can start doing that for him? All I want is to make him happy I'm just not sure how to do that. Any advice??