it is not wrong to think about the future, and anticipate how we may react, our strengths and weaknesses, etc. Also, it the way we have been educated, our brains are trained to do that. Particularly you are quite intelligent and organized, so... how not to think about how all this mess will accommodate in the future and what is your particular role for a better outcome? how, indeed, not have feelings about it? You are able, trained, and entitled to thinking and having feelings about the future now that your wife is pregnant of an unwanted/unplanned child.
But, if you have not been taught to love yourself properly, IMO. you cannot just get over of this negative part of your past and then take care of usual business. It is not just some benchmarks in history, some anecdotes, It is part of your constitution.
It is one of the most important parts of a human being. Oh, and it is the foundation of the capacity of being a parent, as well. You may modify some stuff installed in you in your childhood, other will stay there with you, you will have to learn how to better deal with it. I feel the same and it is hard and sometimes I do not know what to do. It is so good that you are in therapy already.
in fact, dealing with it and taking proper care of yourself (even if necessary having your wife to cope with some stuff by herself without your help for a while) may be the best way for you to be a parent right now. Perhaps it is time to parent yourself