P0ppy - I just read your post and I think the path is more clear than you see:
The OC should get to have her Dad in her life but I have no desire to have the OW in mine. I'm not scared to be alone but I do want another child so much and I think all these details just add to the noise in my head which makes no path clear.
If you make one of those infamous lists so many of us in IC have made.
Breaking it down (based on my reading of your comment):
OC should have WS in their life.
Being involved with OC means WS must have continued contact with AP for a long time - at least until OC reaches adulthood and likely longer on a smaller scale.
If WS is involved with OC then he is involved with AP.
If WS is involved with AP and I stay with WS then I will be involved with AP.
I don't want AP to be a part of my life.
I am not scared to be alone.
I want to have another child.
So looking at those statements if OC is WS's child you think he should be involved in OC's life. As being involved with OC = being involved with AP then either you have to decide if your statement "I don't want AP to be a part of my life" ends with a period e.g. "I don't want AP to be a part of my life, period." Which really means "AP will not be a part of my life." Which is what we like to call a dealbreaker here on SI - If AP will not be a part of your life - if that is a boundary you have to have, and if OC is WS's child, then there is little negotiation for you to remain.
Or is there is a comma after life e.g. "I don't want AP to be a part of my life, but I want to stay with WS more so I will deal with AP anyway."?
It isn't lost on me that the one thing you could have put in that list that you indicate staying is an option for you isn't there - the second clause that I added.
To me, not being scared to be alone is great for you as it's not dictating whether there is a comma after life or not. WS is not the only person who can give you another child, which I know you know as well. So it really comes down to: "AP will not be a part of my life." OR "I don't want AP to be a part of my life, but I want to stay with WS more so I will deal with AP anyway."
I don't envy you - it is a horrible choice to have to make and I'm so sorry you have to.
[This message edited by ThisIsSoLonely at 5:11 AM, Tuesday, September 19th]