Take a look at the sentence again:
Because Henry enjoyed impressing his girlfriend Gloria, he __________ for
the expensive dinner with his brand new credit card; he would worry about
the shocking statement when it arrived in the mail next month.
The sentence requires the simple past of pay, an irregular verb. Paid is the simple past form.
| Verb | Simple Present | Simple Past | Past Participle |
| pay | pay(s) | paid | paid |
Had payed, the form you chose, is a spelling error. In addition, the auxiliary verb had is unnecessary. Before you continue, review the rules for irregular verbs.
Try again to escape Grammar Hell!