That's a tough situation. Perhaps if your wife would just give you some time on the issue then a decision could be made with clearer minds at a later date. What's the rush? Your first child is only 4 months old and he/she is your first. You both may still be in the fog of trying to figure everything out and get a firm routine established. Which may be why you're not really in the mood to discuss a second. There will definitely be a time to discuss a second, but I don't think it's now.