T.M.
Sounds like you need to put a little more effort into having him eat and drink table foods more frequently during the day.
I nursed my youngest until he was 2, but it was just that first wake up in the morning closeness and the soother before a nap or bedtime for probably about the last 6 mos.
Don't be afraid to tell him "after you eat and drink this first Mommy will give you some mommy milk "(or whatever your term is for it). In most cases once they've finished up some other foods as a distraction, the need for nursing on mom will slowly begin to vanish. You might have to get pretty creative with his meals since he's finicky, but he's only finicky because food is still pretty new to him.
He's one and a half, old enough to listen to you reason with him a bit and learn a new schedule that you set in place. If you cave to the whines and cries that's his payoff and you won't get anywhere.
It's hard to quit tho, I'm sure you enjoy it and it wont be simple or easy for either of you.....watching and wanting our kids to grow up is very bitter sweet.