He could be great, just not great for you.
However you should go one more time. Maybe just to tell him you wish to stop seeing him.

I'm really struggling with trust (other ppl or myself) So in the beginning I just went for someone I could imagine spending 50min a week talking to. Seems like a easy thing, but I went through a bunch of T till I find my current one...

You have a good experience with T before so you know how it feels when the relationship is solid. Go with your guts.