My ex was SEI. We both saw each other as interesting in theory, and once we started interacting on a deeper level we realized that we didn't have anything in common. Most of my conversations with him were punctuated by awkward silences and I constantly felt restricted somehow, like he wouldn't respond well to anything I said. He seemed to be the same way. The main conflicts we had were his "complex of closed mouth" according to strat and Te.
I knew it wouldn't be a serious thing from our earliest conversations, but it was near the end of high school and I wanted to get experience before I graduated. Also, I wouldn't see him again afterwards, once I went to college. We agreed that it was just for fun, by the way...

We ended up breaking up earlier than I expected because we kept disagreeing on things.
He seemed to weirdly pride himself on being an "open book" and having "no secrets." He was always skeptical when I wanted to keep something private and eventually he told people about a personal detail I didn't want anyone knowing. He often told people things casually, without thinking of the consequences of his actions.

He seemed kind of ambitionless and directionless, which is just a personal turnoff. He was a decent student but he had a reputation for being unreliable with projects and seemed kind of lazy. He told me once that he "was worried that he'd seem like he was trying too hard, so he'd try to seem lazier, but then he'd end up actually being lazy," which sounds like Te-PoLR to me.

I remember always trying to help him with Te matters; once, when he lost some parts for his hobby, I told him about a service they offer where he could order new parts for free. But he always gave a dull reaction. We broke up when he showed me a website he coded for a political candidate and I noticed he'd misspelled their name. I usually don't correct ppl's grammar but this was obviously important, so I told him. And then later on, he complained about me to everyone, I guess saying that I was a know-it-all bitch or something.