I'm in the same boat as "Should we or shouldn't we?".
I'm hesitant to give outright advice on what you might do, as I am not yet a parent and don't have an SO in the picture myself. But I would say in general that having a baby primarily to please your SO and not because it's what you really want might not be the best way to go. Doing it out of guilt about the situation of his living child may cause more resentment, particularly if things don't go well with the pregnancy. I'd say your situation and not necessarily your age may be the primary reason for hesitation.
My SO was already gone when I found out I was pregnant, and he wasn't in great shape anyway and might have made my pregnancy more difficult by being present. There's also a chance someone else is the father. My pregnancy may sound like a bad Maury episode from the outside, but the truth is, it has changed my life entirely and I'm extremely excited about the great chance I now have to become a Mom to a healthy baby boy in less than 4 months. At the same time, while there have been no signs of chromosomal abnormalities such as DS, I had decided early on that I have room in my life to care for such a child if that's what I was presented with. Can you honestly say the same? Single parenthood will not be easy, but I feel it will be easier than trying to co-parent with someone who isn't prepared to make the effort. I certainly didn't decide to keep the baby for him-- I've made very few decisions for him since becoming pregnant. Even my feeling that, if the baby does turn out to be his child, I should give him the chance to be involved if he chooses to is based mainly on what would be best for my child. The amount of contact I'd encourage would depend on the state he's in if and when the time comes. Since early pregnancy my focus has been on the baby. So I think if you feel circumstances may not allow you to make the baby the primary focus of your pregnancy, you're probably right to hesitate.
Good luck with your decision. Whatever you decide, please base your decision on what you feel you can handle.
Make a pregnancy ticker
Edited 4/20/2010 7:43 am ET by karen2010
I wanted to also note that I was on several different psych meds when I became pregnant and stopped taking them all, even though my docs advised me to be cautious about that. It's worked out for me; hormones seem to be agreeing with me and emotionally, I feel better than I have in more than a decade. Everyone's different, though, and there's no guarantee it would go that way for you. Some choose to stay on Category C psych meds while pregnant because severe depression during pregnancy can be a greater risk than taking such meds. I decided I would try going without them for at least the first trimester, but I always left the door open to go back on if I needed to. The same is true after giving birth-- since postpartum depression is common, especially for those with a history of depression, there's no guarantee how I'll feel later, and I may have to then choose between breastfeeding while on meds vs. formula feeding.
Overall, though, I just strongly feel the time in my life is right to have this baby and I'm willing and able to adjust to whatever happens (short of losing the baby, of course, which is something one faces only for lack of a choice). It may seem like I have a number of reasons to feel otherwise, but I have no hesitation about my decision to continue the pregnancy. But I have no other kids to worry about. Again, if you don't feel the same way, like this is really something you want in your life even if things don't turn out ideally, there's probably a good reason for that.