Hi There.
I am sorry that you have been put into pretty much the most nightmarish situation by your WW.
Cheating is one thing, but having anther mans child puts it on a whole new level.
I know this is hard, but for your own sake you need to try to make decisions using only logic with a view to your future wellbeing, emotionally, but more importantly, financially.
Remove all emotion from the decion making from the decision making process.
In a nutshell your heart cannot be trusted to make the safest decisions, you have to use your head / logic only. Think like a Vulcan would from Star Trek.
It is is easier said than done, but I did not do this and I ruined my future over someone who ultimately was only manipulating me , because I made decisions with my heart, instead of my logic- please do not make the same mistake.
You are stongly urged to assume the worst case scenario (that she will leave you after you are on the hook for CS etc..) and then make decisions based on protecting you from those outcomes (financially first, emotionally second).
See a lawyer and follow their advice.
This obviously means you are recommended to have the OC not deemed as yours (yes, even if that means you should divorce asap should a lawyer recommend that).
Really importantly, as someone else pointed out, why didn't your WW take the 'morning after' pill to at least prevent a pregnancy from starting?
After all she knew she had unprotected sex....
So you really need to KNOW in yourself what you can or cannot cope with in all this - very soon.
You need to really decide whether you are able to cope with her having another mans child for life with you always being below the OC (and possibly even the biological father / OM) in the pecking order.
Will you ever get resentful? Honestly think about this. (for your own decision making)
IMO
I know I personally would be always reminded of how the OC came to be, and that is not fair to the child or me.
Consider:
Maybe you might tell GF/WW she should do what she wants - feels right doing, and that you support her doing whatever her choice is.
Only once she has made her decision (so as to not influence her decision), would your decision be made known, which might be that you cannot live with the that situation of raising another man's child when that child should have been yours to begin with.
If abortion is not an option, has your WW considered giving the OC up for adoption at birth?
Only you can choose for yourself, so again hard choices/decisions await you, please think carefully and seek a legal advice as they will not be encumbered by things like feelings and emotions, and listen to their advice for your own sake.
ETA: Spelling
[This message edited by PhoenixReborn at 4:52 AM, August 31st (Saturday)]