You need to be talking to a financial consultant and/or attorney and SSA rep who is aware of all SS options.
Why are you going after your ex's benefits? Has he passed away? Was he married after you? If he was, that wife may be eligible depending on their marriage.
I don't know all of the specific rules. I do know, my late husband and I typically put in the max each year. Out retirement plans were specific and we planned SS to roll into our plan when we were eligible at the highest rate and age. It didn't work out the way we planned due to his untimely death.
When he died suddenly in 2015, I was told by SSA with my financial counselor that I can get his benefits when I turn 60. IF I were to marry before I turned 60, I would forfeit the benefits. Of course, I have no interest in marrying but he nor I were aware of some of the rules I learned about upon his death.
I would cancel NOTHING until I was 100% sure of all benefits and options.