Don’t even look at what the low-vibing one is doing, once you see, you feel that energy, and then your own energy gets drained drastically, and then it becomes a trap. Pretentiousness cannot hide bad energy. I am guaranteeing you this.
I don’t know how people make it look otherwise but not creating a complete boundary with an ex who still has feelings for you is a disrespect to your current partner. Being friends with an ex is okay when both of you have ‘moved on’ in every sense of the phrase. ‘Been there, done that’. I blocked people completely from my life till they learned that they did not and could never have access to me like before no matter how much I loved them in the past. Boundaries are crucial. Do not play innocent whereas in reality playing with two; trying to get security from one in every sense and mental satisfaction from another. It never ends well.