A couple of thoughts:

Can you try writing ex-T an unsent letter about how she failed you? Just getting your thoughts down on paper can sometimes help experience the anger.

Is your ex-T in your thoughts a lot, like every day? If so you need to change that situation because as you say, it cant be good for your health and current relationships to stay stuck in the past so much.
Perhaps you could see all the time you are losing as an opportunity to embark on a new hobby or project? Or, in other words a good aspect about the situation is that at least it shows you have a lot of energy to invest, can you find a way of redirecting that energy into something healthier?