What's the difference between claiming someone as a girlfriend vs a long term friends with benefits?

I don't know the difference. I've actually only had 2 men claim me as a girlfriend my entire life and those relationships never lasted past 4 months. Whereas my longest relationship was a friends with benefits for 8 years and we have children together. We don't live together but maintain daily communication and social dates for the kids that ends in him staying over/impregnation.

I've been proposed to by the friends with benefits but ended the engagement but we still continue to sleep together
What's the difference between claiming someone as a girlfriend vs a long term friends with benefits?
Post Opinion