string variable

How about this? Split at the string ", TXT" first (there's a space between the command the the T) and grab what's to the right of that string. Using your examples, after the first split, you wind up with:

TXT=my Variable Value, with spaces and other characters
2=More Data for Second variable
3=Additional info,

Then, split each substring at "=" and grab everything to the right of that character, giving you:

my Variable Value, with spaces and other characters
More Data for Second variable
Additional info,

On the very last substring, you may need to remove the last comma. I wasn't sure if the last TXTn= parameter would contain a command at the end or not.