This is something that has come up in surveys.
Women will generally tend to fancy men who are around their own age, so the age of the blokes fancied will rise as a woman ages.
Whereas, men will generally fancy young women around 18-20 regardless of their own age. And often feel entitled to dating the young women regardless of the wishes of those women.
Right now, I'm 52 and wouldn't be interested in a bloke younger than about 45, and more likely to look for someone about my own age.
I think my sister who is 55 and her husband who is 70 would be pretty upset if someone described their 39yr marriage as 'distasteful'.
I'm someone who ended up in a 30 year relationship with an abuser I met when I was 18, and he was 26, the age gap at that time was significant and I was definitely groomed.
So yes, I'd worry that someone who gets into a relationship with a man who is almost double her age (of 16) when they met is also likely to have been groomed.
And that kind of age gap at the start of the relationship can result, as with me, in an imbalance of power in the relationship. So here, I think the sister may just be lucky.