Maritsa, it just makes no sense socionically for you to have friendships/relationships with a Delta Dual who gets increasingly mean as you know him better. No one describes Deltas as "horrible, mean, vindictive". Certainly not another Delta. However, we Deltas sometimes have those issues with Gammas and Betas. From
here:
Beta: Deltas tend to see Beta types as people who "dream big" and always want to turn things into grandiose endeavors, yet can't manage day-to-day affairs effectively. Also, Beta types seem unwilling to consider things from the point of view of others, which gives them a streak of meanness and cruelty.
Gamma: Deltas tend to see Gamma types as driven and reliable in personal and business relationships, but not sufficiently understanding of people who want to pursue their own individual path in life. Gamma types sometimes become too demanding and can have a streak of vindictiveness or spitefulness which prevents them from being accepting and forgiving.
The above, fits, doesn't it. When I have been struck by the surprising meanness of someone, its often a Beta or a Gamma. I see that in your conflicts, here, too.
The exhausting conflicts you had with that one guy you dated are just too, too unheard of for ANY Dual, especially a Delta Dual. They sound exactly like the conflicts in Conflict Relations. And since your Conflictor happens to be a Beta, your not only experiencing conflicts with him but deeming him "horrible, mean" fits with Beta. Another "tell" is that Conflict partners are both are equally exhausted by the conflict of the relationship. So, if your guy was all relaxed about the problems you had with him, then maybe he is not your Conflictor. But if he was
also stressed out by the conflict, I do not see how you could have been anything but Conflictors. NOT Duals.
What seems like "shocking meanness" from the SLE to you and me is, instead, "acceptable, understandable and not-shocking" to his Beta Dual... and probably okay with his Activity and Mirror, too.
You need to understand so you can forgive. Then you are free. Truly free! It feels great, too. But betrayal and what feels like betrayal are the hardest things to forgive, and can take a long time. I know. But understanding is a fundamental stepping stone in the process. That's why I say. It will help you heal that sore that is still there.