Am I sinful for having caused one of my relatives to take out a loan to pay off a large sum of money on my behalf, which I was forced to borrow to settle a debt I owed, a debt I had incurred from my own money to help my fiancé?

If your relative borrowed a usurious loan to help you pay off your debt, he has committed a great evil. And if you requested it from him or assisted him, you have shared in the sin; for borrowing with usury is one of the major sins, except in cases of extreme necessity, such as fear of perishing. Paying off the debt of an insolvent person is not among these necessities, unless the delay leads to great harm, such as imprisonment, and there is no other way but a usurious loan. And if you took the money from your employer without his knowledge and consent, you have betrayed the trust, and you must repent and return the money to him.