A loan means that the bank lends you money. You can't borrow it for several years, but you can't borrow it for time. Time has passed. The installment is to pay back the money today, not tomorrow, and next month. Love without installment payment means that you can't pay separately, you can only invest once. You can't love you today, not tomorrow, but the day after tomorrow.

Good luck! (If you have any questions, please ask them. If you are satisfied, I hope to adopt them.)