The phrase often carries a feeling of relief after ending a troubling situation or relationship. Once she cheated, I needed to be rid of her to move on.
Pro Tip 2/3
Not Instant
Being 'rid of' someone takes time, it's not immediate like simply walking away. It took months to be rid of his influence in the company.
Pro Tip 3/3
Not Always Negative
The phrase can imply a neutral or necessary change, not just a negative one. Retiring meant he could finally be rid of daily commutes.