Note: My interpretation of the passage is incomplete as I'm not all too familiar with the topic. Any pointers would be appreciated.
Divorce, the end of marriage
This is no enigma
Just a shameful stigma
We have split apart for good
A malevolent stance taken as it should
The former spouses have separated. It's pretty shameful, and it's typically the result of hatred towards each other.
Our contract now null and void
Marriage is a legally-binding contract in many jurisdictions; divorce terminates that contract.
Desiring to inhabit a separate planetoid
The former spouses live separately.
For what we may have created
now in despair, not appreciated
Children are inevitably upset as a result of a divorce.
for we'll pay for our sacrilege
In many religions, marriage is considered sacred, and divorce sacrilegious.
Once we dine with our heritage
Inheritance problems can come up as a result of divorce. It is impossible to stay out of hell, your heritage = what has been passed down to you = DNA. Your past relations in hell.
Take our past in unrelated directions
no longer our paths have intersections
The former spouses separate and never want to meet up again.
This heartfelt decision
Has caused this incision
In many legal systems, divorce is a decision made by a judge in court.
although different, still a toad
the reference to the frog turning into a prince happily ever after in marriage. This now divorced, your still a frog
So now we divide our surrounding
separate haemorrhoids not corresponding
haemorrhoids = piles, the metaphoric description of dividing the assets of the marriage and splitting them, which are never correspond. Ones pile is always worth more.
Once classed as my property
Now free of the depravity
It was once common knowledge that the wife was property of the man (still is in some communities). Now free of being an object through divorce.