Sorry, OP, but I have to say, "Tough cookies! Buck up, he's a teenager!"

My teen is no easier on me and I'm his natural mother.
Okay, in all seriousness, we're having problems like that between DH and my son. DH came into his life when he was 3 and everything was FINE. The father isn't in our lives, so DH became "Daddy." This past year or two has been a total nightmare and DS is reverting back to treating DH like a stepparent. It was getting to where I was seriously considering leaving because I constantly felt as if I had to choose between them. DH and I were fighting horribly and both he and DS felt as if I was betraying them in some way. It was so frustrating.
We finally came to a comfortable arrangement, even if it's not the most ideal. We had to go through quite a bit of counseling to come to this point. DH and DS just have sort of a mutual existence where I do 99% of the parenting, and discipline and so on. DH has no expectations of DS, other than to treat him with respect. If DS gets in trouble, I handle it. If DS needs to do something (say take out the trash), I handle it.
It does suck for me, but compared to the way things were even 7 or 8 months ago, it's a whole lot better.
Good luck to you. Don't be afraid to find a good counselor if things don't straighten out soon.