Donald Love's fate after the Love's Disappearance mission is something that has puzzled many who have played GTA 3 Definitive Edition. Such a topic was even relevant back when the original game came out, which is important to note since the remaster didn't change anything storyline-wise.
This character has never appeared in a game that canonly took place after 2001. He does appear in GTA Vice City and Liberty City Stories, but both games take place before GTA 3 Definitive Edition does. Hence, gamers won't find the answer to this question in a sequel.
However, Rockstar Games did shed some light on the matter in a Q&A back in 2009.
Donald Love's fate after his last mission in GTA 3 Definitive Edition
In the Asked & Answered from September 28, 2009, one gamer asked:
"I'd like to know the whole story behind Donald Love. What was in the package? And why did he run away with the Asian guy? I always assumed it was human flesh or something, lol, because he's a necrophiliac and all."
Rockstar Games responded with the following:
"No one is quite sure what happened to Donald Love. He certainly crossed a few boundaries and was trying to find a way back to normality. Whether or not he managed this, and what happened to the elderly Asian gentleman are matters we cannot speculate on."
Rockstar Games purposefully left this character's fate as ambiguous as possible. It might be disappointing to some gamers who wanted a definitive answer, but the game was full of uncertain endings to various storylines.
This plot point didn't change in GTA 3 Definitive Edition
It is vital to reiterate that GTA 3 Definitive Edition follows the original story 100%. There is no deviation in the plot of any of the GTA Trilogy remasters. Thus, that's why a 2009 Q&A is relevant for the 2021 remaster.
Nothing has changed since that Asked & Answer session. It's also worth noting that the 3D Universe ended with Vice City Stories being the last game created for it. Every game from GTA 4 onward has been for the HD Universe, which is technically a different fictional universe from its 3D counterpart.
Since no new games are being made for the 3D Universe, gamers shouldn't expect an answer to Donald Love's disappearance. GTA 3 Definitive Edition was the last real chance, and it was a faithful remake that didn't explore this plot any further than before.
Other ambiguous storylines in GTA 3 Definitive Edition
Donald Love's fate isn't the only thing in this game left unknown. What happens to Maria after the gunshot is heard in the finale is also an enigma. Rockstar Games stated the following to a question about Claude shooting her in an Asked & Answered from December 15, 2011:
"We're not sure about this. Some think he did, and some think he didn't. Certainly in an original version of the script, Maria had a longer, really annoying speech, but then someone in the audio department wisely put an end to that. Quite what that means for Maria, who can say."
Similarly, Claude's fate from the same Asked & Answer was revealed by Rockstar Games as:
"He certainly isn't dead. What else became of him, we don't know."
Donald Love's mysterious disappearance is just one of several unresolved plot points in GTA 3 Definitive Edition.