Know in your heart that what ever happens is for his best interest. Maybe he needs the jail time to knock the reality into his mind that drinking is a problem & drinking & driving is NOT ALLOWED.
I know that your common sense tells you this. Think that if he doesn't get the help he needs to stop his drinking that marriage to him might not be a good idea......so in reality, I think that what has happened to him now could be the best thing to insure that he will want to change, so that your marriage in the long run will stand a chance of being successful.
Your support during this time is important as long as he is serious about changing & getting in control of his drinking (which means stopping drinking completely).....the whole situation could draw you both closer together as long as you know not to enable his drinking behavior with your support.
Think your friends, your T, & your church activities are keeping you knowing what is right & the truth about the situation. Staying in reality is the most important during this time. Staying in the day to day analyzation of how things are going is important. Think you will be fine & your BF will be fine as long as you put your trust in God & follow His guidance, then all this will become a thing of the past, but a good reminder of how serious drinking & drinking & driving really is.
Much better that it be jail that he has to live through then a constant reminder of a horrible accident that might have killed someone because of the drinking.......let it be a good learning tool that God has provided to instill the seriousness even deeper.
Know you both will be fine as long as you both put your lives in God's hands.