Father's affection for daughters under 6years

Here's what a mother wrote to Funmi Akingbade of Sex and Sexuality in The Punch

I noticed that each time my husband plays with my daughter, he gets a hard on. Just yesterday, I noticed that his trouser was stained with sperm after helping me bathe our daughter and changing their clothes for an outing. This has been going on for sometimes now. These girls are below 6years. I am always not comfortable when he offer to take them to school or do anything for them. Should I divorce him? When I confronted him, he threatened to beat me up and take the girls to his parents.

Funmi's reply:
Anything can make a man develop a hard on. Mere thought of sex, sight of a nude female, smell of a good perfume and so on.

But when the sight, touch or feel of one's daughter becomes a turn o, something is definitely wrong, especially when the object of arousal istriggeredby a child. When safety measure is not taken, it may lead to a case of incest. I am of a strong opinion that if you handle this in a sensible way, things will not get out of hand or lead to a divorce.

Should this be happening at all? How does she begin to deal with her husband's attraction to their children?
smh