If our adopted son moves out will we be responsible for child support. We have no intention of asking him to leave. He threatens when ever he doesn't get his way at home

Do you mean would you have to support him monetarily to live somewhere else? No you wouldn't have to he is l8 and perfectly able to live out on his own. So next time he threatens, hand him walking papers and say, okay, you had better get a job then ! That would draw him up short.

He's 18 he can move where ever when ever and that's that. You don't have to pay for his other place or anything that would be for him to do.