Regex Question: separate string at the last comma in string

My string pattern is as follows:

1233 fox street, omaha NE ,69131-7233
Jeffrey Jones, 666 Church Street, Omaha NE ,69131-72339
Betty Davis, LLC, 334 Aloha Blvd., Fort Collins CO ,84444-00333
,1233 Decker street, omaha NE ,69131-7233

I need to separate the above string into four variables: name, address, city_state, zipcode.

Since the pattern has three to four commas, I am starting at the right to separate the field into multiple fields.

rubular.com says the pattern ("(,\\d.........)$"))) or the pattern ",\d.........$" will match the zipcode at the end of the string.

regex101.com, finds neither of the above patterns comes up with a match.

When I try to separate with:

#need to load pkg:tidyr for the `separate`

function library(tidyr) separate(street_add, c("street_add2", "zip", sep= ("(,\d.........)$")))

or with:

separate(street_add, c("street_add2", "zip", sep=  (",\d.........$"))) 

In both scenarios, R splits at the first comma in the string.
How do I split the string into segments?
Thank you.