I've not watched all of it, but the main character is presented as blatantly bisexual (or pansexual depending on your perspective) though he is not immediately interested in the other main character who is blatantly portrayed as gay (though he is by obligation seemingly forced into hetero marriage in order to produce an heir). Also, his family seems to be fine with him being openly affectionate towards this other boy... so I dunno maybe they thought it was queerbaiting cause mixed bag? Or maybe there is something later on.
There are some parallels to YuYu Hakusho's story I think or even Noragami. The whole premise is that he saves the boy's soul from vanishing by spiritually bonding with it for the rest of his life and is thus enslaved to him in a way. They have some rather overtly sexual toned scenes as well between them. It is worth noting the other main guy shows no real interest (in fact blatant contempt) for the girl he is proposed to.