Other answers have suggested avoiding explaining that your husband has autism and agree that it could be a good idea. However, if you still want to tell your acquaintances about the autism without them badly judging your husband because of that, here is how I suggest doing it:
First of all, you need to know that, in my experience, it's the people who have the less knowledge about autism that tend to judge the most. Knowing that, if you want your acquaintance to be less judgy, I will need to educate them.
For this "education part", you have two options:
One, educate them first, then explain that your husband is on the autism spectrum.
Two, do the opposite and start by telling that your husband has autism before explaining what it means.
Personally, I will go with the education option first.
If you start by telling that your husband has autism, people will immediately have a (probably false) representation of what it is and what it means. Then, when you will start explaining what it actually is, they might get suspicious and think that you are making up excuses for your husband. This means that you will have to fight twice as hard to convince them it's not the case.
However, if you start by telling them more about autism, they are more likely to listen with an open mind as they won't suspect/think that you have an ulterior motive to tell lies to them (even if, in both cases, you won't lie).
At the end of the explanation, or even later, you can they drop a casual:
Oh, by the way, my husband is on the autism spectrum.
This way you show them that it's not a big deal and that they shouldn't take it as one either.
It's important to note that this technic probably works better if you wait at least a couple of day after the explanation of "what is autism" to tell them that your husband is on the spectrum. This way they had the time to assimilate what you talk to them about and to accept it as the truth. They are then less likely to think that you are just "making excuses" to your husband.
Introducing the topic of autism:
To educate your acquaintance about autism, you need to bring the topic on the table first. In order to do that without it sounding too forced/weird, I will suggest using a technic I called "The random fact conversation" (I already talked about it here).
The idea basically is to choose a weird/unexpected/funny fact about a topic (here, autism) and start a conversation by saying:
Did you know that...?
I use this technic often with my family and there are quite used to it.
Another way to educate your acquaintance is to send them interesting articles/video about autism. You can introduce the message like this:
I read this article and found it very interesting, so I'm sharing it with you now.
However, depending on your relationship with said acquaintance, this could be seen as a little weird (for example, if you never talk in writing and only see each other once a year).
I bit of background about me:
I'm, myself, on the autism spectrum. Some time ago I had to announce to my family that I was autistic (it was a lat diagnose). Everyone didn't take it the same way but it seems that the one who already had good knowledge about autism took it better than the one who didn't.