From that point things started to. In your exact context, the real underlying implication is probably more don't go too fast for your dating partner rather than.for. From that point things started getting complicated.
PPT Asymptotic Notation in Algorithm Analysis PowerPoint Presentation
In grammar in use book, the bold part has been considered as correct answer. Regarding the to getting forms, i. From that point things started to get complicated.
However book titles are allowed artistic license.
He did not succeed in getting the job though he tried his level best. To get is the normal form and would be best for everyday use. So, i like getting/ to get to the station in plenty of time.