Basically, you're right. Summarizing what I tried to post earlier and will probably show up at some point: I didn't really know what I was getting into, and none of us had really talked about how things would go if/when I moved in. I was in some serious hurt from leaving the boyfriend and my family disowning me, and I am 100% sure I am to blame for part of the blowup, but it doesn't take away the fact that I feel he pushed too hard.
After I slept with R the first time L's husband told me he was hurt because he wanted to be with me, and I said basically maybe someday. Because I didn't know. I didn't know how things would go. But he basically took that as a starting point to assume it would happen one day, and he wanted one day to be soon. Started pressuring, got angry... triggered me into remembering early abuse from my father. Bad combination.
To his defense, I had slept with L in his bed with him in it (JUST sleeping, just needed to be close), and I am sure there were other things I did that he thought were leading him on.