The 'rule' against splitting infinitives is long outdated, Believer, and it is a common and accepted practice by all but the most prescriptivist grammarians. Concern yourself only if your teacher demands it.
Placement of the negative particle is normally before the
to (negatives tend to front, as in
I don't think he's coming), but this is a different sort of decision, because its placement can change the meaning (examples from
Quirk):
His hardest decision was not to let the children attend summer camp (= his hardest decision was another decision)
His hardest decision was to not let the children attend summer camp (= his hardest decision was denying them camp).