Eep. That's quite scary. One-too-many-times... Is it really possible to find someone who will never hurt you/break your trust? Not even ONCE?
(I'm just musing here... no hard feelings.

)
Which makes me wonder... What does it take for one to break your trust? I'm assuming the standards must be high(er than average), since you're only giving everyone
one single chance.
Hmm. I was trying to be a bit teasing but I guess my tone didn't come off right. Here are some examples.
One work friendship I've distanced myself from lately is a women who is recently engaged. She's asked me to go wedding dress shopping with her (both times at the last minute), which I've done willingly even though she's said I'm not invited to her wedding (destination wedding with family only). She bugged me for weeks to set up a double date with this INTP I recently met, and then flaked on it at the last minute. She said that we could try for the following week, but didn't make plans. She had a temporary assignment at a different facility 30 miles away, so I figured while she was doing that she would probably be too tired to hang out or do girl's night (which we've done several times over the summer). So I didn't contact her when she was working at this different facility. When she gets back, she doesn't tell me and doesn't talk to me for two weeks and then asks me if there's something wrong?

Then when I try to set up plans to go to lunch with her she always has some excuse for why she doesn't want to go.
One guy I used to date knew I was looking for a new place, and suggested to me that a friend of his in his research lab was looking for a new roommate. This move enabled me to live closer to him, but pretty much doubled my commuting time (even though it was much cheaper). The move didn't go well, the roommate and I didn't mesh well either. He dumped me three weeks later (because of an argument I had with the roommate) and I ended up moving closer to work the next month. I don't talk to him anymore.
Another guy I used to date used me to move closer to his work (basically I let him move in 'temporarily' and then he didn't tell me when he found a new place), then dumped me. We were involved in a gaming group together, and I got pushed out of the gaming group after the dumping. A woman who I introduced to the group (who I would hang out with regularly - at least twice a month) let the friendship fall apart and eventually moved across the country. She let a year go by without talking to me and then when she decided she could use me for a security reference she e-mailed me to ask. This was after multiple attempts on my part to call, text, e-mail, etc. otherwise ask how she was doing after her move.
Another guy I had a "friends-with-benefits" relationship with was consistently flaky; would set up dates and cancel them at the last minute multiple times before I finally called the whole thing off.
One INTP I dated and I parted on what I thought were good terms. I found out shortly after the breakup that he hid a significant portion of his life from me. When I asked him about it he said that not only was he never going to tell me, but that he thought I knew about it anyway. This particular INTP always made a big deal about being "self-aware" and was into learning about human consciousness and taking care of "his half of the relationship".
I put up with a lot of crap before I write someone off. I know a lot of it is
*my* fault because I put up with it, but it's not like they do one minor thing that pisses me off and I say I'm through. If I don't feel someone values me in their life I don't stick around.
My relationship with the ENFJ in my life isn't a romantic one (we're both ladies and we are, more or less, friends). Either way, I recognize that problem in our relationship too... because I admittedly don't talk to the ENFJ in my life that often (I do see her every day though; I guess you could say we work at the same place). She doesn't appear to take it hard, so I've always been assuming that it's alright to leave her to herself every now and then... especially because she's surrounded by people who like her and care about her.
I do make conscious efforts to remind her that I care about her. Just a couple of days ago I sent her a short email telling her how special she was to me. The only thing that's unnerving about our relationship IMO is that while she tells me that I mean a lot to her, she rarely tries to express (the extent of) her feelings for me. Which is why I always have to question myself whether I really matter to her or not.
Any thoughts on this matter?
Words from an ENFJ aren't just lip service. If she said that you mean a lot to her, your friendship does matter to her. What kind of expression do you want from her? Maybe she feels that her affectionate bubbly self would be off-putting to you?
It's not that hard to maintain a friendship with an ENFJ. Meeting for coffee or lunch with greater frequency than once a month will suffice, although for me I'd like to meet with my closest friends once a week. If she feels you don't have the time for her she may or may not try to revive the friendship, and if she's felt rejected multiple times she won't try at all.