I've been seeing someone now for just shy of 2 years and I've really noticed how much differently I approach things now. Obviously not perfect, but things I simply didn't understand or know how to deal with constructively in the past seem at least familiar now. Essentially, I have a clue now.
This isn't an "end state" but rather a process of learning and developing that continues - but has gotten to a point where I feel like a much better partner than I probably was in the past. I didn't have terribly great role models to emulate in this regard and I wasn't born knowing how to participate in a romantic relationship. But I've at least had some experience in what can work, what doesn't work well, and where I need to focus to avoid mistakes I've made or others could've handled better.
I mean, my relationship history is approximately similar, and I’ve got to say:
This qualifies me to give approximately zero relationship advice, and has gained me approximately zero insight in to the human condition.