I guess I would ask husband some questions before going forward with paying an attny even for a consultation.
If she had been 6 months older and actually 18 at the time of the crime would he feel any different? If he would not be suggesting this if she was already 18 then perhaps you need a further discussion of his reasons for doing it now. Does he really think that she is not going to re-offend in the future? If so, then I guess I could see some point to trying to help her now. But if he thinks she's likely to end up in jail again then what exactly is the point of helping her now? How will it help her in the long run?
If he would still be wanting to pay for an attny if she was 18 then I will tell you that this issue is NOT going to go away, assuming that difficult child 1 continues on her current path. So then the real question becomes - how often and under what circumstances are we going to help her like this in the future? Do we want to set this precedent/expectation with her? If you're going to do it this time, how will you decide whether to do it next time?
Looking down the road like this may help you both get clearer on why you are or are not going to pay for an attny and what is the exact nature of your apparent disagreement.
It sounds like he is trying to protect you from getting hurt. It's a sweet gesture but jail is not the only place where bad things happen to people.
If my spouse and I were having this disagreement and I decided to go along I would insist on putting a $$ limit on what you are going to spend on her defense in advance. I would make it clear to any attny that took her case that you would NOT pay any more than that no matter what. I'm thinking that you could easily find yourself with a bill for $5,000 or more here depending on what happens. Are you in a financial place to do that? If the per hour charge for the attny is $150 then you are only looking at a total of 33 hours for $5,000. That includes prep time, meeting with your difficult child 1 time, court time, telephone conversations, etc. And then there's the photocopying costs, the certification and delivery costs, the filing fees...it goes on and on.
I hope you find a compromise that works for both of you.