I am not here much but it pains me to hear of your sufferings Eve
I can't really explain why people do what they do, I think behind a lot of people's actions there is a lot of suffering and sometimes it's jolly well inexplicable.
I remember getting dumped on Christmas Eve in 2006, that wasn't a pleasant experience!
I have learned not to turn the actions of others in on myself and then reflect it back outwards (I guess that's a definition of bitterness?) I've had my share of despair and loss, and am more realistic these days, but not bitter (at least I hope).
I haven't much to say except I hear and understand your pain.
For some reason this poem sprang to mind:
Wild Geese
You do not have to be good.
You do not have to walk on your knees
for a hundred miles through the desert, repenting.
You only have to let the soft animal of your body
love what it loves.
Tell me about despair, yours, and I will tell you mine.
Meanwhile the world goes on.
Meanwhile the sun and the clear pebbles of the rain
are moving across the landscapes,
over the prairies and the deep trees,
the mountains and the rivers.
Meanwhile the wild geese, high in the clean blue air,
are heading home again.
Whoever you are, no matter how lonely,
the world offers itself to your imagination,
calls to you like the wild geese, harsh and exciting
over and over announcing your place
in the family of things.
(Mary Oliver)