We can't choose who we love.
Our rattional minds are shouting 'No! Go away and stay away!' but our hearts - which always have their way, say 'I love you so I rogive you ...'
Eventually - and youhave obviously reached that stage - you realise that this person is simply causing you more pain than pleasure and no amount of wanting it to work is going to make it any better.
The cutting out of this person from your life is painful, and you will grieve for a while, but as time passes, you will see that you did the right thing, and being alone is honestly better than being in a destructive relationship, even though it doesn't feel like that right now.
The positive thought to hang onto is that you are free to move on and re-build your life, and from where you are now, you can start to do that.
It's not easy, but it can be done, and the good people on here will support you when you need it.