A friend's daughter

My longtime died of cancer and it wiped the family out financially, by family I mean his daughter then 27 he lost his wife to a car accident in 2019. With the death of her father, she lost the family house and the small business they both had run together. Still with a large bill for her father's hospital stay, no home and no job. I then 42 offered her a room in my house, I'm 5years younger than her father was we'd met in the fire department in our twenties. Both moved on to other careers, I inherited money and properties, he had started their family business with his then wife. But we kept in touch and only lived five miles apart, I was with him when he passed. He had asked me to watch over his daughter, I'd agreed too. I'd never married and told his daughter she always had a place to live with me if she wanted too. She did, mainly because she was still grieving and hadn't any idea of what she would do next at the time. I saw to it she got everything she needed and paid off the remaining hospital bill, the funeral was paid for by me because I'd arranged it as she wasn't up to it at the time. I didn't want replacement for either of the bills and had told her so. But as she stayed with me, she noticed me looking at families with children with what she called a longing look. She realized I wanted to have children of my own, so she offered to have a child for me, more if wanted. We got on very well and always had; I'd known her most of her life. I was a bit shocked at first, but she explained it would improve her future greatly and only she wanted in return was marriage. As my wife her future would be secure and like me, she wasn't into dating. I said I would think on it, but every time I did after the offer, I'd got aroused. So, I thought why not and we married next to the graves of her parents. She quickly got pregnant and gave me a daughter than two years later a son. We've been married four years next month and she might be pregnant again. Our marriage is perfect I think she is a devoted mother and a great wife. Our lives are based around the children and we enjoy being married.