Yeah, I've also had a hard time now that the Wiki is gone. I already finished the country road but haven't got that part yet since I don't go home often nor sleep there. How about this, just save your progress if Ste visits you and keep saving if there are choices in the conversation in case you might choose the wrong one. That's what I've been doing to avoid a choice that will make a character like me less.
Also, I think one heart doesn't mean the character will get jealous or love you less if you interact with a different character together. I read the Wiki about Ste before, and maybe they are having a threesome, but that's just a probability because I haven't got it yet.