I don't see why Lana would need to change the name. We all know that anything she says/sings sounds like silk so even if the person was someone named Greg or Allen whatever, she would make it work with the song. It is interesting though that she could have just said "he" taught me that rather than a name but, it wouldn't tell as much of a story.
Ultraviolence is obviously about a toxic relationship that both people are addicted to. Because, while Jim seems to be abusive it sounds like she was no better saying lines such as "He used to call me DN, that stood for deathly night shade" doesn't really paint a picture of someone who's nice. Obviously they're both crazy for eachother in the worst way. This song is seriously dark just like she promised. She literally wants to run back to him she can't keep that feeling away she wants it back she wants the Ultraviolence. The crazy toxic life they had together. It's almost like a drug that kind of feeling.
That's just what I think of the song though personally.
AkaLizzy liked a post in a topic by TheKingofHorror in LANALYSIS: Relating Songs To Known/Assumed Relationships