Hmm, I think this general subject is going to vary from one INFJ to the next, in terms of their own ability to set up boundaries and be OK with those boundaries - i.e. a healthy mix of selflessness and selfishness, and realizing that stating your needs and your own boundaries is in fact not a bad thing. Maybe this ties to enneagram? Surely upbringing too. I just know that while I have a few INFJ friends who I think have substantial difficulties with creating boundaries, I've always been more... stingy and selective with what I give, I guess. (btw, I'm not trying to make myself sound better, or anything, I'm just making an observation)
Also, I guess to me it seems sort of natural for the relationship to dissolve whenever it's discovered it's not mutual. Sometimes it's not possible to know this right away, just based on the nature of how relationships evolve and how you simply can't know everything from the get-go, but also over time if you're able to figure out your own needs/boundaries right from the beginning, and communicate those, then the 'right' relationships will follow as a result, and the relationships that wouldn't fit your own needs/boundaries wouldn't develop.
I think the inability to say 'No is a result of devaluing your own needs/self, habitually, and not realizing that again, it's OK to take care of yourself!! I mean, really! I guess this is the biggest part I have trouble relating to when it comes to other INFJ's... I've never had a problem saying No when I'm overextended. I mean, don't get me wrong, I'll go to great lengths with those I care for and my good friends, but those lengths are not a burden. I'm happy to do that. It feels natural. But when/if resentment would kick in, or I'm feeling I'm 'obligated' even if I really don't want to, to me that's a sign that I should look at it further, and ask myself WHY I'm feeling that way and WHY in fact I HAVE to do said thing. Because... most of the time, we don't. It's 100% in our power to say no and to build the types of dynamics we want in our life.I guess saying "no" and learning how to do so without guilt is probably the advice you'd give me... I have started just avoiding people who ask me for favors. What if the only reason I don't want to do a favor is because I know they'd never do something for me? Is the appropriate response "no, and here's why?" (I always feel like I have to explain). Or is it, "No, too busy". Or just, "I'm sorry, I cannot do that." Maybe I'll try the latter... Is that what you do ceecee?
To the OP -
I do hear what you're saying. But I think people for the most part are going to go with whatever we project/communicate to them. And, I'm not sure I can judge/blame them for doing that. So even though it would of course be *nice* for others to reciprocate what we do for them, first of all if it's not in their nature to do so, we probably don't have the 'right' to have that expectation out of them (this is where you ask yourself why you're in the relationship in the first place, or why you and you alone are giving so much). There's that possiblity. But secondly, there's the fact that they only know as much as we convey to them (unless of course you're dealing with another infj or someone who knows you well, etc ), so if we convey to them that we can take whatever's thrown our way, isn't it reasonable for them to think that that is in fact the case, even if it isn't? So as uncomfortable as it can be for us, it does fall on us to express/communicate our emotions/feelings more often, IF we're beginning to feel overwhelmed, uncomfortable, resentful, etc, and just in general to try to start embodying those expressions more regularly from the beginning. Not that it's easy, of course. It's hard to create potential conflict or show our less favorable sides.