He was with Jeffree for about 5 years right? So I think he long knew how awful Jeffree is, but maybe things got unbearable. The relationship always gave me a vibe of abusive. I always felt that Nate had zero say in anything, and how good can a person feel being with someone as controlling and manipulative as Jeffree and not having anything of their own? Nate had no real job, no education, nothing... he was fully dependent on Jeffree... at some point even though living off someone might sound good, it can take a toll on the self esteem. Plus lets not forget that Jeffree exposed their sexual and intimate life all the time... I can't imagine Nate feeling good about this, specially being the chill and private guy he seemed to be. Nate looked awful in the last months with Jeffree and he seemed to be stoned all the time, maybe to cope with the relationship. And if I remember correctly, Jeffree made him pretend they were still dating for the fans in the last months. Remember that new mansion house tour?
Nate stood there in the video acting as if he was moving there too and they were still together but they had already broken up. They even had to make excuses for Nate's clothes not being there and the fact that apparently Jeffree had given/thrown away Nate's clothes and Jeffree was pissed at people who started speculating they had broken up... a total circus. I don't think Nate is a saint if he stood with Jeffree for 5 years, but I can't imagine how awful it must have been for him to be with someone like Jeffree... maybe money isn't worth everything.
If the rumors that something recent and awful about Jeffree will be exposed, I wonder if that's what broke the camel's back in their relationship.