It is a problem on your end, or many people would yell about it.
So what could it be? Here are my guesses:
1) The patch (any patch) will change several files. This means writing on your hard disk. (If you have the game installed on a SSD, you can forget this possibility)
If this writing caused a bad block in one of your game files (not necessarily the game exe itself), it could cause a crash. The bad block - or some glitch during patching - could have created bad data.
2) You are using Galaxy - this program is not always stable. Many people seem to have issues with it. I never used it. You do not want to download the game again, I understand this. But if you would download the game from GOG directly and install it manually, you could also store the install files somewhere safe, and never again need to download them.
3) The crash log you attached shows an out of memory error. Do you have 8 GB or less?
What I would try:
1) Backup all your save (just to be secure), deinstall the game, but not the saves. Install new, apply patch. Delete your user.setting files (they are generated if they are not there). Recheck your settings in game, and try to load a save.
2) Deinstall Galaxy, kill it completely. Download manually, then you have full control where and how to save your game install files. I do not think that Galaxy does a full check of every game file, i.e. a full MD5 or CRC check of the entire content, because this would take quite a while. It will check, if the file is here, and if it has correct size. Yet if some data in a file are corrupt, this checks will not find out.
3) Check, if the out of memory report could be true. Check if all of your memory is still recognized by Windows, and the BIOS. Check, if some 64 bit program running on your PC besides the game could have eaten away your memory resources.
And - do not rule out a defect with your PC. Sometimes memory develops errors. Since nearly no normal desktop or laptop PC nowadays has ECC checked memory, such an error will always lead to peculiar problems and crashes. But not always - programs which need a lot of memory have a higher chance to be mapped on a bad memory address. TW3 needs lots of memory...
Hope this helps a bit...