By 1874, he and Mabel's father were partners. Mabel's parents were worried by Aleck's obvious interest in their daughter. She was only 17, while they mistakenly believed him to be about 35. In the end, they permitted Aleck to tell Mabel of his feelings. He promised to change his life for her.
Some promises are harder to keep than others.
To Mabel's dismay, Aleck firmly maintained his habit of working well into the night and sleeping through the morning. Shortly after their engagement, she informed him that she was painting his portrait. Mabel and her family were also distressed by Aleck's tendency to jump from one subject to the next. Aleck was furious at this. He was also distressed by his parents' reaction to the engagement.