Hi L.!
There were some great ideas mentioned already - one more option is the Family Club - www.thefamilyclub.org There's a playgroup that meets most Tuesday & Friday mornings from the fall to the spring, and then there are special events & play dates here & there and Wed morning music classes that start back up in January. I don't usually go to the regular weekly playgroups because I can be a bit shy in groups, but...my son would be devastated if we didn't go to his Wed morning music / fun class!
Your husband & son could attend one "Coffee & Play" (as the Tue / Fri playgroups are called) for free - your husband could see if that was something that would work for you guys. If so, then you could become a member ($35 now or $17 in January) - that's the downside...that there is a cost for membership involved (classes are extra too)
There's a range of ages of kids who are there playing, but they're all under 5. There are also tons of toys to play with, which is really nice. It's located in Shorewood in the church near Sedniks on Oakland (but not affiliated with church)
Anyway, that's another idea!