Of all the things to teach in schools, you'd think conflict resolution would be a priority, right? Somehow it never made the cut. So, here are some comments, which are limited and certainly not enough for all things, but hopefully a good start, whether for relationships or neighbors or random strangers.
1. anybody gets to want/request anything they want, without fear of judgment, period.
2. the simple fact of wanting something, no matter how apparently reasonable, does not entitle you to a goddamn thing. period.
3. emotional blackmail is not allowed, i.e. A's action X causes B's feeling Z
2+3. just because it hurts you way more doesn't make you right about everything
4. deflecting is when the subject is X, and someone says well yeah Y, and Y, while a valid concern/point, isn't exactly relevant to the current point. Response: yes, let's make note of and return to that, but, for now let's work out X.
To that, add something about personal space, and your right to your own privacy, and you have decent ground rules for working it out. A corollary to those basics is that either/or absolutes like right/wrong, should/shouldn't, good/bad, moral/immoral are pretty much useless. You say what you want, the other person says what they want, and then you discuss to what extent each desire impinges on the other, what the value of this or that thing is to each person, and how much each would be willing to pay or give up in order to get which thing. Terms need to be clear, and the physics of them has to be practical (e.g. no "you can't piss me off any more"), and any residue of emotional blackmail, especially as it leads to entitlement, is to be removed from the transaction. Especially, nobody has any kind of right not to be offended.
Of course there will be grey areas and situations for which these guidelines are insufficient, but very often they're enough to help work it out. And if you can't, then hopefully either party can choose to exit the relationship, and the other person can think whatever they want to.
Suggestions for improving this page much appreciated.
Oh, and first/also, learn to work out your thinking: maybe some of the solution to the problem really is mostly up to you.