Thanks for relating your experience... I think my identity searching has been like a mid-life crisis for me as well. I knew that my last ex was someone I was going to marry, and the failure of this relationship has me trying to understand who I really am. I lost myself in the relationship and became codependent...taking on her values but not really. So when I didn't have them to the same degree she did, she felt betrayed at what she perceived as fake.
My ex-husband was also an ISFP...and they were the only two major relationships I ever had. He was raised by an unhealthy, manipulative ESFJ...and he was selfish and deceitful as well.
I recently called my Infp ex selfish as well because her need to park her car in the driveway seemed more important than my son's wellbeing. I needed to be able to back out so I could take him to school...so I moved her car. And because I didn't discuss wanting to take him to school that morning with her first, she was upset on principle. Even though I moved her car out of the way so she wouldn't have to.... and it is dark in the morning and 2 kids were hit already this year riding their bikes to school. She told me she wanted me to park on the street from now on (it's my house). And what's weird is she parks on the street most of the time anyways...
And she was paying half for groceries... until last week when my 9 yr old left a half eaten cereal bar on the counter before school. I know morning's can be crazy, and she might not have been hungry..... so I was just going to wrap it up and save it for later. But she started doing that inferior Te stuff and criticizing my whole parenting, that I was raising my kids to grow up to be horrible people to live with. She kept picking at me for an entire 10 minutes while I was silent until I couldn't take it anymore and told her to shut up. I usually never would say something so mean, but she pushed me too far.
She will not accommodate herself for other people....and my ex that was an ISFP was the same way, though it was a much nicer relationship in terms of conflict since he was a 9.
But now im wondering, am I seeing them as selfish because they truly are selfish?
Or am I seeing them as selfish because they're not accommodating themselves to other people's needs like I think they should do?
I sorry that your relationship just ended. That can definitely set off a need for self-examination. The pain of such can be useful in the path of growth, if we can face it.
Fi doms are selfish, in a way. They struggle to act contrary to how they feel and don't accommodate others well.
FJs are notorious for becoming codependent

hi

, especially as they lack a strong sense of self-love, seeking fulfillment in others. Most codependents are children of narcissists and/or mentally ill. NFJs in particular are horrible about becoming over accommodating to others.
Your story of the car in the driveway is very typical. I have seen such behavior and among most Fi users I know.
It doesn't make them bad people at all. It just makes them very different from a Fe user.
There is a definite difference in the approach to the world between the two groups and crossover is often painful. Fe users get annoyed that Fi users don't even seem to understand the simple rules of life that Fe rules take for granted. Fi users tend to feel such "rules" are hostile impositions from an external domineering force.
I had an interesting conversation with my ESFP son the other day. He views all the family rules as optional and meaningless, so he breaks them regularly. I was trying to use the idea of traffic laws to explain that family rules are just like laws that are there to help things go more smoothly.
When we approached the stop sign, I said, "I don't get angry because I see a stop sign. It doesn't bother me that it is existing. I know it is there to avoid accidents and help everyone."
He responded, "Well, you don't really need to obey stop signs. It really isn't necessary......."
Sure he is only 11, but I was very surprised by his statement.
For a FP, a FJ setting forth of rules and ideas become, at times, as hostile impositions from the outside. Many Fi doms in particular want to be islands, independent of external pressure.
FJs understand naturally that we impact others and so we are cautious about how we interact with them. And we know we are highly influenced by how they feel and they by us.
For me, I never suspected I was codependent. I didn't know I had a complete lack of boundaries. I completely ignored my own feelings. I was highly in tune to my wife's feelings, so it was extremely painful anytime she was upset and harmony was disrupted.
To break out of that, the codependent needs to set forth boundaries. To stop accommodating so much. To love themselves and get in touch with themselves. To get angry when someone starts treating them badly. e9s are usually out of touch with themselves, just like most FJs, so, getting more in tune with themselves will help them grow and avoid these issues. Finding anger and interacting with it is a powerful thing for e9s.
Codependent relationships are stable, as long as the codependent person is the doormat. As soon as the start pushing themselves forward, it disrupts the relationships. Either the other person has to improve or the relationship dies. It is a difficult process. For me, I was very lucky and my marriage has greatly improved as I have gotten healthier and focused more on my needs and my wants and myself in general.
Back to selfishness, both sides can be selfish in their own way. My ESFJ teenage son is lost without someone with him (especially his INTP twin). He gets demanding and aggressive in his neediness. He wants to watch over his brother and take responsibility for his brother and be needed by his brother and so he hates his brother not needing him. The INTP twin is smothered by his Fe and pushes him away.
FJs want harmony (as do 9s, as you noted), which can be selfish in that they want others to act in a certain way (even if it seems like the best way to act and most people would seem to agree with that). FPs don't seem to see the need to keep harmony if something bothers them.
One thing I learned with my wife, is that when she gets on one of her Te tirades, I put on what I call my Fi filter. I ignore the details of her words and instead try to understand what she is expressing behind the words.
FPs often can't get the words out to adequately express what they feel, if they are even aware of what they are feeling in the moment. Te becomes an improper mechanism to express the feelings, especially about something close to their depth of feelings.
I love Fi users. I feel a pull to them wherever I am. Most of my friends growing up were ESFPs. There is an unconscious pull to what we don't consciously use, so FJs are pulled to FPs and FPs are pulled to FJs.
If you are a FJ, then you repress your shadow Fi enormously. But it isn't weak, it is just unconscious and neglected.
However, there is a point in life, where FJs need to turn Fe inward and look at that shadow Fi, just like FPs need to turn Fi outward and look at the shadow Fe. It is extremely awkward and painful (midlife crisis and such) but can be extremely rewarding if one can actually do it.
I can only wish you the best. Perhaps a fully developed and healthy FJ will no longer feel the pull to FPs.
I hope this was not too long of an answer to your question...........