It sounds to me that the core problem here is that you are in an adversarial relationship with your son. This can make it very hard to have even normal conversations, because the assumption on both sides is that the other person is going to act negatively towards the other every time you open your mouth, or he opens his.
It's very hard to repair something like this, and it won't happen in a day. Your son will have to be a willing partner in this; he's old enough to understand, and to put the effort forth, but you'll have to start more than likely.
The key will be to avoid any statements that make him out to be your adversary. This isn't to say you shouldn't still hold him accountable for his actions, but you need to find ways to do it that aren't accusatory, aren't "against" him. Perhaps be more understanding of the "little" things, and focus on the "big" things. He's approaching (or perhaps at) a turning point in his life, where he's no longer dependent on you or his father; this means you're going to have to change some of how you enforce rules, and probably means the rules need to change, too. A teenager should have substantially more freedom to act, and make mistakes, without a parent's correction; some of the struggles now are undoubtedly him wanting that freedom.
Most of all, you need to have more interactions with your son that are not the result of him crossing a boundary, but instead are positive interactions. What can you do with him that you'll both enjoy? Are you both runners? Are you both interested in certain television shows? Rollercoasters? Find something you both enjoy, and do it with him. The more inherently positive interactions you can have, the better for your relationship, and the easier it will be to have the more difficult conversations when they do come up.
You should ask your partner to help with this, as well. Not just ask for advice; but rather, come up with a plan, and ask for his help implementing that. My wife is amazingly helpful for me, and I think I am as well for her, in helping each other limit our negative interactions. If she sees I'm having a hard time with one of our kids, she offers to step in. If I see she's having a hard day, I offer to take the kids on a walk. We both give each other feedback after interactions that could've gone better - constructive feedback, not criticism; just gentle reminders that we let our emotions take over sometimes. This is one of the most important things we can do for each other.
You should ask your partner to do the same - explicitly, if needed. After you have a poor interaction that he was in the room for, ask him how you could've done it better. Ask him to take over when you feel your emotions getting out of control. Don't be afraid to put your discussion with your son on hold for a minute while you talk to his father about how to handle things.
Finally - this isn't irrecoverable, and (though it sounds trite) many, many people go through this kind of period with their children, particularly at this age. You're a good mother, clearly, and you can get better at it - we all do. More experience, and careful thought, will guide you through it. Just focus on positive interactions as best you can, and get help from the people you rely on when you need it.