If you love your DW then give her the child she wants ... That the baby might be a void-filler or a career-stopper or whatever else is irrelevant.
Why should the op give in? Why should he bring an unwanted (by one parent) in to this world?
None of it is irrelevant if the op doesn't want it.
Having a child to make someone happy seems to be right up there as a pretty good reason tbh I can't even begin to make sense of this post. I was an unwanted pregnancy, my mum didn't want me & wanted to terminate the pregnancy, but my dad (and her brothers) persuaded her to have me, telling her she would love me etc, in the end she continued the pregnancy to make them all happy. But she didn't ever bond with me & we haven't spoken for over 20yrs now. We had a terrible relationship at home, she failed to show me any positive emotions, resented me & showed it constantly, and treated me very differently to my siblings. It has caused all sorts of issues in my adult life & relationships.
Having a child to 'make someone happy' is bloody terrible advice & can have HUGE repercussions for the child. I am saddened that anyone could advise this, to be honest.
Children bring their own love. What a terribly naive thing to say 
I do not imagine you relationship will ever be the same. It won't be the same if the op agrees under duress, to have another child he does not want, either! It is lovely that almost everyone on this thread thinks a baby will fix everything. It's bloody wonderful that no one seems to have the experience of being unwanted & unloved by a parent. It's bloody fairytail like that almost everyone thinks the op should have a baby (he doesn't want) and they will all end up happily ever after. And bloody delusional too. There is a huge chance that if the op has a baby, he will resent it.
What then? A child's life in tatters because the MN majority said he should do it.
I suppose what I find cold about your post is that you have no desire to create a child with your wife. So because he doesn't want a child with his wife, he is what? I don't want anymore with my dh, that doesn't make me cold or any other negative spin you would like to call it. It makes me someone who knows her own mind & is happy with what she has. The op isn't in the wrong here, we need to stop making the op out to be the bad guy!
I don't think you love her as much as you say you do. Why? because he doesn't want anymore children? So that means he doesn't love his wife...OK! Big leap to make there. I don't want anymore children, I had my tubes tied. My dh wasn't sure & did, a couple of times, talk about wanting another (we have 2,). That doesn't mean I don't love him. It means I am done having babies & raising them & at 40, I don't want to start again. As is my right.
And this is the op's right too...he should not feel pressured into having a child he does not want.
You can't try and pressure her into not wanting this. yet you'd quite happily see the OP being pressured into having a child he doesn't want? Your whole post is very disrespectful towards the op. Would you be filled with such vitriol if this was a woman posting that her new dh wanted a child, because he didn't have any & she said no, because she had 2 & wasn't wanting any more?
No, I bet you wouldn't. Yet because this is a male it is ok to completely rip into him & call him unfair, etc.
OP - I think you should have a baby....I've never known anyone who's had a baby and said, "Oh - we don't love the baby. This was a bad idea." My mum did. And the effect on me of not being wanted was/is profound.
Just because you have never met anyone, it doesn't mean they don't exist. Plenty of people regret having babies, they just don't talk about it because that is not something you do, is it? "I regret having children" it's just not something you do.... Yet there is a facebook page called just that....
49 is not too old. If the op feels it is too old for him, it is too old. End of.