Not true.
Your husband is correct. Adult guardianship is designed for folks in comas, with severe autism, Alzheimer's, etc. It's designed as a kindness, to keep people safe/protected who can't do it themselves. Who cannot make decisions, period. Not people who make decisions other people don't agree with. And it's hard to get. If the person it's being applied for is physically able to say "no", then they're able to make decisions, and almost it's impossible to get... unless they're also applying for it, and even then it's hard to get approved. Because most people take their freedom -and the freedoms of others- very seriously. People fight wars for freedom. We enact laws protecting freedom. Freedom is very important. You're not alone in believing that.
I'm hesitant to say it's entirely PTSD, however, because it may be... or you may have some other things fueling this fear. Young mom = Post Partum Depression, hormones a bit imbalanced, & sleep dep = very likely as well. And I'd hate to see you solely focusing on the lessons you learned in trauma if they're only coming
out because of something easily fixable.
Speaking as a mom (and therefore sleep deprived), with PTSD, who had antepartum depression (PPDs cousin, who shows up whilst pregnant, instead of after birth)... I'd really urge you to talk with your doc. This stuff is hard enough without an easily fixable physical thing making it 10,000 times worse.