While we saw only a few of his visits to her (for example, in "Day of the Moon"), the Doctor implied that he visited her very frequently. In "The Wedding of River Song", there was this exchange on the subject between Dorium Maldovar's head & the Doctor:
- DORIUM: And Doctor Song, in prison all her days?
- DOCTOR: Her days, yes. Her nights? Well, that's between her and me, eh?