Everything, unfortunately, that has happened to us holds weight.
We are what we have done and what has been done by others.
The mistakes that we are all stereotypically bound to make will undoubtedly have been made by others and hopefully we may recognize them for what they are and avoid them.
Past relationships help us make current ones better.
Past relationships can help us not get into a relationship that will be toxic.
And however obviously the facts stare me in the face
I cannot resist falling in love.
I cannot resist falling for a girl
who shares many of the same circumstances that my partner in a previous (toxic) relationship.

As appealing as it may be, never let your heart make your decisions for you.
Not when you have a perfectly stable brain allowing it to beat.

Above all I hold this principle to be true:
Do all the good you can do
and good will find you.
Albeit in a roundabout way, typically.