Explanation:
Marriage is the legal union of two people. It is a legally binding contract that states two people are committed to one another, financially and emotionally.
A life partnership is a union of two people who have chosen to commit to each other for their entire lives but choose not to legally marry and not enter into any religious or spiritual bond.
Answer:
The difference is that one (marriage) is legally binding and the other (life partnership) isn't.
I hope this helps :)