It's a difficult poem, so no two people will think it means exactly the same thing. All I can say is what I see, and you have to make up your own mind. The Narrator is thinking of his Love, sometimes talking to him/her in his/her thoughts. Gender is not specified, but I'll make the arbitrary choice of using "he" for the narrator, and "she" for the love. It is not clear to me that she is still alive. When he says "mine is the only medicine now", it tells me that she is no longer there to keep him company, so he is forced to rely on himself. I interpret the sentence "Now we're so much closer to death than we were then" as meaning that she is dead and her death, having already happened, is close in his mind. Now he feels like a beast of burden, an ox, carrying the weight of both of them. He has become both people. He carries her memory. She and he are the same now, so the phrase "ox you" (which makes no literal sense at all) identifies the two words. "Ox" and "you" become the same. He is the ox, but he also is her now, so ox=you. By putting the words next to each other, the poet is making the statement that they are the same now. He wants her back again. He asks her to infuse him with her scent in his oxen fur. It's a very beautiful image.

What a beautiful poem. I have never heard that expression before - I don’t think it is common. I had two possible thoughts. (1) It could mean “hug and kiss you” because “o” can symbolise hug and “x” can symbolise kiss. (2) It could mean “carry your burdens” because earlier the poem it says: I had to get old to carry both buckets yoked on my shoulders. Sweet and bitter waters I drink from. People can use a yoke to carry two heavy buckets of milk/water on their shoulders. Here I think she is talking about as she got old there were both happy (sweet) and sad (bitter) memories for her to carry. But animals, particularly oxen (= many ox) are also put into a yoke so they can pull heavy carts etc. We call animals that pull heavy loads like this “beasts of burden”. So when she says “ox you” I wonder if she is saying, “I can be your ox and carry your burdens for you.” These are just possible interpretations though - interested in other’s ideas???

Maybe it's kind of emotional expression: like ancient "damn", could it be?😜