confused!!!

Hi guys I have previously been in this site for advice and further on into my relationship I'm back!! I am into my relationship now for 3 half years we get on really really well have had some brill times and also sone really bad times but just pulled together as you should!! This weekend has really made me step back and think about this relationship, he states he cares for me very much in which I do hand on heart believe him but when it gets to those three little words he just can't do it!!! I do think I need to step back again give him space what do you all think??? I'm sure there are people in the same situation as myself come forward and share some light on this !!! As it's dark over here
Thank you for taking time and reading this