Using lookbehind, to make sure the " is not preceded by a \
import re
data = 'var v = "this is string constant + some numbers and \" is also included "\r\nvar v = "and another \"line\" "'
matches = re.findall( r'= "(.*(?<!\\))"', data, re.I | re.M)
print(matches)
Output:
['this is string constant + some numbers and " is also included ', 'and another "line" ']