Wow, you have done an amazing job! The national average of breastfeeding is only 3 months, and you have for over 1 year. Congrats!
Obviously there are unending benefits of breastfeeding. Even though his nutritional needs are different now, your milk is still good for him and provides added nutrition that is more suited to his needs than formula or milk would. Have you talked to your pediatrician and asked for his opinion? If your little guy is a picky eater, the pediatrician may say to continue for his health. However he may also say that your son is fine and that a vitamin supplement would help.
Another thing to give him that is totally natural and packed full of nutrition is a green smoothie. Babies and young children (in my experience) love the sweetness of them. Mix 1 handful of spinach, 1 peach, and 1 cup water in a blender or Vita Mix until it's liquified. Serve it in a sippy cup. It's pretty good. You jusy have to be sure it's not chunky. You can also look online for other kinds of green smoothies to make.
As for the bond, you will have that with your son forever. He looks at you totally different than he does his father or any other caretaker in his life, and that will never go away, even after breastfeeding.
I think it is as hard on mom to wean as it is on baby (sounds like it may even be harder on you!). It's so nice to have that quiet, relaxed, comfortable time with baby.
Look at it this way. If he is fine without it and you are wondering whether to stop or not, I would stop. He doesn't seem to "need" it anymore, so maybe its time to move on.
Best wishes and lots of smiles to you!