So far as i have written, despite him being one of their longest college friends, Jake does not know Milk is plural. For a while, anyway. No idea through undergrad, and he probably only learns early in graduate school, if ever. Milk never told him because they were worried that he would be weird about the topic, because a previous Boring Cisgender Man (their hs boyfriend) was not kind about it. Im under the impression that they're good enough friends with jake that he'd be unfazed (hes very go with the flow anyway) but they're so used to hiding themselves from him that it's sort of... default?