Correction

Greta:  Right, but are you and Marni lovers? Did you used to date?

The correct form would be Did you use to date. I think it’s a typo.

The speaker was asking whether or not he used to date in the past. E.g. He used to date meaning he used to see someone in the past. Thats OK. I went through the link that you forwarded me. I got your point. But my point is the sentence that I am talking about here is an interrgative one and as you know for n interrogative  sentence we bring the auxiliary verb first and then put the main verb. In this case the auxiliary verb will be in simple past tense i.e. DID and the main verb will be in simple present tense i.e.use (not used coz the helping/auxiliary verb is already in the past) because the speaker is desribing a thing or habit of the past.

E.g. Did you use to smoke?

Incorrect form: Did you used to smoke?

Please correct me if I’m wrong….....

Best regards

Abhishek

Sorry, you didn’t answer my question?

That’s OK. I appreciate your prompt response.

CHEERS