Boyfriend or Husband? Which do you want to have a child with?

This post is purely out of curiosity. To those out there who choose to have a child with a boyfriend rather than getting married, what are your reasons? I find this interesting because I see A LOT of women going through the trouble of actively TTC with an SO but not being concerned with marriage. I find it interesting, so don't take offense.

EDIT: Thank you all for your responses and respectful conversation. I asked this question to gain a better understanding of what drives others in life, love and child rearing. Many different perspectives were represented. I hope you all can see that we can discuss our differences while keeping tolerance in mind. 🤞

EDIT 10/10: Okay, wow this thread has grown very large. I don't think I can read every response anymore lol. Thanks everyone for your input!