Men find it really difficult to be monogamous due to being wired up to spread their dna.
Forgot to respond to another aspect of this.
Lots of people, male and female find it hard to ve monogamous ... But who's asking them to be??
If you don't want to be in a monogamous relationship, don't get into one!
If you got into one and have realised you don't want to be in one, speak to your partner and see if they're willing to have an open marriage of be polygamous. If not - leave. Be respectful and civil but leave.
They are lots of people who want to be polygamous, have a relationship with one if them if you want a relationship. Of you don't want kids to be aware of that lifestyle, keep it to your child free time. There are people called baby sitters, most people have some family helpers.
Do you know what the issue with men like this is though?
They don't want to be polygamous, they don't want an open relationship. They want their wife or partner to be exclusive with them, while they're not exclusive with her, they don't want honesty of equality. They want to have their cake and eat it.