Being a long term
successful third requires some very specific things in my opinion.
Experience in life similar to what others around them have.
Maturity - the kind that comes with experience as well as simple character. I find it hard to accept that someone who is 19 has had sufficient time to accumulate enough life experiences to reach the level of maturity I am referring to....sorry if this is not well received
Self confidence - "This is what I need". This area took me a while but first I had to figure out what that was lol!
Self identity - be able to stand on your own two feet so to speak.
Belief that they are loved and truly love the partner they are with.
A clear sense of purpose - why am I here? Plain and simple..no existential mishmash of fluttery words, just ask "why am I here? and answer it.
I am Redpepper's boyfriend because I love her and enjoy the love she returns to me in all the ways we communicate. BUT
I am a third
because I love Redpepper and feel I can contribute to the positive health and flourishing of her primary relationship and the life of her son
Sounds like you have all of this in the equation LadyMcbeth. I am glad you are moving forward and embracing this relationship with the understanding that no one person has the answer, we're all learning. There is no expert in this Field no matter what they claim. There is a collection of experiences and a body of hypothesis.
Thanks for sharing all of this
Peace and Love