PD I am probably the last person to give advice, as you will see from my other thread on here, but as someone going through an affair (or possibly not now as he appears to have gone all silent on me....) if I were you I would try and think of the best and worst outcomes, long term/short term in each case ie whether you did or didnt keep the baby. Without sounding incredibly trite, whatever decision you make is for the rest of your life, and will affect the rest of your life. I can only imagine it must be so hard to make this decision or even to think about it when you are already going through everything else. I feel I cant make decisions about simple things until I know whats happening with my man...I have no idea how I would manage in your position.
however, for me, one of the things I was first attracted to with my OM was how he felt about his children, how much he did/does for them etc, he said to me many times (as I'm sure your OM did to you) that his children were the best thing in his life, they would always come first and whilst he wanted to be with me it couldnt be at their expense. Where am I going with this? Well, your baby is his child too. In your situation, if I was asked how I would want my OM to react, it would be to say that ultimately it was my choice, but if I wanted to keep the baby, which he hoped I would, he would be there for us both, however difficult it was, because that would be his child just the same as those he already has at home.
Possibly idealistic I know, but I dont think knowing he had suggested I should have an abortion - or discussed it with his wife - would mean I could ever feel the same way about him, I'm not sure I would want to have his child knowing it wasnt what he wanted....but then again Im not sure I would have an abortion knowing that would be the outcome which would suit everyone, except for me.
Whatever happens, I hope you come to a decision you are at peace with.