Question for Aquarian men?

I am woman who is in love with an Aquarian man, my same age. I know he loves me in his own way. However, what will make him mine forever? We have the best time and conversations. I love his friends, for i know they are just as important to him as his family. We are hardley ever apart and our chemistry is great. What is keeping him from jumping in with both feet. Do aquarians not like to put thier heart out there? He is a widower but also ended a 8 yr relationship about 4 years ago that went real bad real quick. Since then he and I have been good friends, we have crossed the line before but decided to go back to platonic friends, but I really love him and want to know why he went back to friends and am I potential life mate for him. I understand the long leash thing, I understand to give him space, I just need to know how will I know if he is worth my patience are aquarians slow to move into a relationship? any advise is surely appreciated!!!!