Husband relapsed; what do I do? He was clean for about 8 months and resently confessed to using, we have been married nearly 3 months and I'm not used to any of this and could use some advice.

What's his drug of choice?

I am with Nikki on this.....

heroin and now mixing it with zanex, he is currently in detox which is a good thing. but i just dont know what to do he is going to start going to an out patient program that im going to try to attend as well.
iv just never gone through this and dont know if im even helping or not.

You can't do anything. You love him, but if love could treat addiction there would be no addiction problems. It's a very helpless place to be, the spouse, but you'll have to get on with your life- if you have kids, or work, or pets, whatever, you maintain the life he can return to when he's cleaned up and sober. That's all you can do.

Don't let him start a methadone maintenance program. There's no point and methadone is worse than heroin. Often, methadone addicts take methadone with Xanax because it gives the user a high very similar to heroin.

Just make it clear to him that you will maintain your life together while he cleans himself up; until then you can't do a thing. And for him detox is just the start. When done it doesn't make him sober. He needs some form of counseling to understand why he's using in the first place, which is what he would start after detox.