You've got some good advice here from those who've been through the turmoil of raising boys. Pick your battles, observe from afar, feed him regularly, practice the formula of 90% listening/10% talking, keep your emotions in check, tolerate outbursts instead of reacting, and don't lose your sense of humor. Set a few, but firm, lines that cannot be crossed and don't waiver. Let him know you and your husband will help him figure out any major problems but will let him work out the rest without interference because you have confidence in his ability to make good decisions. Be diligent about not offering unsolicited advice or prying. Be his mother but don't treat him like your baby boy. Make him treat his girlfriends(!) well and let him mourn his heartbreaks alone. Never criticize his friends; instead, invite them into your home and feed them. Be disappointed instead of angry when he makes mistakes in judgement.
Console yourself with the thought the boy you snuggled with only a year ago is still there, but there are also the beginnings of the man he will become a few short years from now. Realize that the surly teen you see in your home isn't the face he shows to the rest of the world. Other parents will call your son charming, and you'll be thinking the same about their kid. Both of you will be right--and wrong.
And don't forget to hug him at least once a day, even if he looks impatient or rolls his eyes. Tell him it's a mother thing--something you need to do now, and forever and all time. And one day, in the future, that surly boy will be telling you to drive carefully and let him know when you arrive safely at your destination. Both of you will have survived your trial by fire and emerged, intact, on the other side.