Verb to with -ing

[diplomacy]

What I studied was after 'to' we use infinitive verbs,
But I have being was shocked when I found these sentences, so please explain it?

1/ I am looking forward to seeing you.
'To' functions as a preposition. You look forward to a noun or gerund.
2/ He would prefer playing to reading.
You prefer one noun or gerund to another noun or gerund. It's similar in meaning to "I like playing more than reading".
3/I am using to reading.
'To' functions as a preposition. You are/get used to a noun or gerund.

[5jj]

My apologies, diplomacy. I meant to reply with quote to your post, and instead edited it. . The answer is still there.