J.W.
If you want support, you'll definitely find it here! I'm a nursing mom and my daughter is 27 months old. As a previous poster mentioned, there are some great benefits to the little one who nurses up to the age of two and even beyond that. Maybe what you can do, since it sounds like he is already cutting the bedtime nursing out himself, is to give him a push in that direction and try to not nurse at bedtime. That's one option. It would still be gentle and loving but would give you a little time to yourself.
Just want to mention too that you may not have to do much yourself. As your pregnancy continues, your milk supply will drop down due to changes in the hormones and little ones react differently to the changes. Some wean just from that because the milk just isn't there. Sometimes they come back after the baby is born but many don't, deciding that they're "big kids" and don't need what's baby's. Some decide that nursing along with baby gives them some time with mom so it just really depends.
Other than cutting the bedtime one (which again is up to you but it does sound like he's heading towards that himself), maybe just leave things be and let nature take its course. Nursing during pregnancy is just fine. If you can have sex, you can nurse (and I've heard that this can help the uterus prepare better for birth). You don't have to let people who aren't supportive know you are nursing and if you get a lot of grief, let them know that there are benefits to it for however long you nurse. Sixteen months is still very young and the immune system isn't even fully mature until around the age of 6 or 7. Plus, if you have a picky eat, breast feeding reassures you that your little one is getting SOMETHING in their diets. If you are currently nursing in public, you have the option of ending that if that makes you feel a little more comfortable. I have done that with my little one but then, I never felt comfortable nursing in public, even when she was a newborn.
Hope this helps you out a little.
J.