Helping a friend

I'm quite well off both financially and career wise, at 35 "single" not in any relation when this all started. A longtime friend 29 lost her job and was struggling financially and have a hard time finding a new job. Luckily for her she had no loans, but with rent and other expenses draining her limited savings. I loaned her money, as she is a friend, we've never dated or in any relationship other than just friends. The amount I loaned her increased slowly, finally she had to find another rental as the one she had was too expensive for her. I offered a spare bedroom of my home as a stopgap, she gratefully accepted. Still loaning her money when she needed it, not a worry to me, but to her. Living together she soon knew all my secrets basically, nothing shocking. I wasn't dating anyone at all, which stood out like the large nose on my face. Finally, she decided to help me out and herself at the same time. She had dated since moving in with me nothing special in any of them. She straight out offered me sex, as sort of interest on the money I'd loaned her, not to reduce the amount. Claiming it would also give her sexual relief as well as me. She isn't a centerfold, but I think she is pretty always had. After thinking it over decided it could hurt to give it a go, an awkward start but we soon relaxed enough to start really enjoying the sex. Overtime she just slept with me every night instead of the nights we'd sex. Finally, she got a job, I'd been promoted and was required to travel and was also entitled to a PA. No prizes for guessing who I chose, sex continued even after she'd paid me back. We didn't think of our sexual satisfaction as the relationship it had turned into, but while thinking one day I realized I really loved her. So, I asked her to marry me, she was somewhat shocked at the time but promised to think it over before replying. She thought it over and came to the same view as I'd done, so we've married last month and are now trying to start a family.