You say "I ended up marrying my best friend. And I do love him very much, he treats me well, and does everything in his power to make me happy and he loves my daughter like she is his own. And we now have a son together."
The rest is noise.
"Love" vs. "In love" is a childish comparison.
The fact that he loves you, your daughter and has had a son with you, alone, should speak volumes about his character.
Yes--I can pinpoint decisions/choices in my life that has "closed a door" in some regard. I'm 48, so I've got a fair amount of life experience on which to reflect--the breakup with a very wealthy friend, surely heir to a successful family business, a college major that I loved, but not necessarily a high-earning guarantee, waiting until I was independent and secure before getting married, and a late-in-life (39) pregnancy & delivery to name a few.
But, you know what I've found out?
Life is generally what you make it.
How does the song go? It's not having what you want--it's wanting what you have.
So--if you don't want what you have--YOU need to find a way to change that. I don't know you or your situation. It might be about debt, a high mortgage, keeping up with the Jones', or lack of additional education, lack of a plan--more the feeling that you are being "carried" down the river of life, drifting, without the ability to make a change. And that's simply not true.
There are MANY SAHMs with low household incomes that make it work. It's hard I'm sure. It might involve evening/weekend work for you or a second job for your husband but it CAN work. Sorry--I'm not a big believer in throwing my hands up and saying "I give." I am a believer in leaving the cave, killing something and dragging it home.
Good luck identifying what it is, exactly, that YOU (and your husband where you can work as a team) CAN DO to make the changes you'd like to see!