Dan,
From what I figure out… its your outlook about things and how you take things. Try to understand that you are feeling neglected now bcoz your wife devotes more time to the new one. You might feel that she is careless about things and other stuff. sometimes you may even find her screaming or yelling at you for no reason and al this makes you feel lonely. You start to think where you went wrong and why things have changed so dramatically. But the fact is you are not the only one.. Most new fathers undergo this phase in life. they feel ignored and sometimes even start to blame everything their past, the spouse and even the new born.But what I suggest to you is just involve yourself with the routines of your family. Try to understand your baby though remember your wife is prime care giver.. It will be tough to gain their confidence initially. Your wife might point out a lot of mistakes in the way you treat the baby. You may know that you are corect but still allow her to tell you. Its just that she knows better what to do. At times she might intervene but just ask her if you are correctly handling and slowly gain her confidence… get to chanching diapers and clothes. Don’t think any work to be menial.. JUST LOVE THEM BOTH WITH A CLEAR HEART AND YOU WILL SEE WITHIN A FEW MONTHS EVERYTHING WILL BE NORMAL. WHENEVER YOU WANT TO GO TO THE PAST JUST GO KISS YOUR BABY AND THE MOTHER. YOU WILL FIND BOTH ENJOYING IT. FORGIVE THEM AND YOURSELF EVERY MINUTE..AND BE A PATIENT PERSEVERE