Originally Posted by
AJBopp
Don't Do it, AJ....Don't Do it, AJ....Don't Do it, AJ....Don't Do it, AJ....Don't Do it, AJ....
Gonna Do it.
Cap went back for the express purpose of snipping off all the branches and not having any straggler lying loose. He reunited with original Peggy in original timeline, and live 75 happy years with her in original timeline. The thought of creating an alternate Peggy, living without him, would have been horrifying to him and caused him to live all his life in torment.