It’s not about what you’re obligated to, it’s about the emotional attachment to children that won’t necessarily remain in your life.

As for adoption, you try that with a person you’ve known for a year or less, see how that works out for you. But yes, if they agree, then sure, i think adoption is fair.

What is not fair is having someone responsible for and bonding with your kids, regardless of gender, and never giving them parenrsl rights.

If they adopted kids it would be their kids, so no issue.