Soler not always followed by the infinitive?

Soler not always followed by the infinitive?
 

Well at first I learned the simple rule 'Soler + inf.' but today I came across the following:

'Los fines de semana solía quedarme en la cama hasta más tarde.'

The infinitive is quedarse, so why here is soler followed by quedarme?

Thanks in advance.

The infinitive that has 'se' tacked onto its end is a pronominal infinitive. So, the conjugated soler is still in front of an infinitive; it's just a different type of infinitive. The conjugation is in the 1st-person, so the pronominal portion of the infinitive must agree with that person. Hence, the 'se' is changed to 'me', the 1st-person reflexive pronoun.

Thank you!