As a new mom, you've already seen quite clearly that maintaining an intense commitment to gaming just won't work for you and your baby, but for some reason, your husband can't or won't see this. It can be very hard for new dads to accept all the sacrifices inherent in becoming a parent. While a child brings so much joy and love into this world, it also means that dad and his needs become number three (or lower if you have a pet) on the priority list. It requires giving up the idea that your wife is there primarily to entertain you and life is basically about your fun when you aren't working. It also puts more pressure on work and career because a very vulnerable little soul is now totally dependent on your ability to put food on the table and keep the heat on.
I'm not trying to justify the way your husband hasn't "grown up," but I do have some sympathy for why it might be hard for him to give up a tried-and-true pleasure for an often stressful and frustrating family life that he may not feel well-equipped to handle. Just because he is an ace gamer doesn't mean he has the first clue about how to work a baby. It's very hard to make a macro for bottle feeding and you can't simply reboot when they bug out.
As the solution to this problem will require some real soul-searching on your husband's part, and it may require him to give up something that has played a big role in stabilizing his psyche, having some sympathy for him might be a strategically good place to start, though difficult if you are feeling angry and neglected.
I would suggest a serious heart-to-heart about the family's priorities and needs. It isn't just the absence created by gaming that is the problem here. It's the moodiness, irritability, and tantrums. You expect these from the baby but not the husband! Gamers with chronic habits that border on addiction often show this kind of restlessness and crankiness. They may also be thinking about gaming when not actually playing which brings another kind of detachment.
Your husband needs your help to remember what is at stake here and make some decisions that will profoundly affect the well-being of his progeny. If he can acknowledge something needs to change, you've made a good start. If he finds he still can't control himself, then he should truly seek evaluation and treatment from a qualified professional. Gaming is clearly one of his problems but his immersion in the hobby could also mask a mood disorder or some other mental health issue that could well respond to assistance.
Dr. Mark Kline's neighborhood in New England resembles his favorite movie from childhood, Ice Station Zebra, starring Rock Hudson, Jim Brown and Ernest Borgnine. It made for a great 7th birthday party in 1968, but much less enjoyable when you have to shovel. Have a question for Dr. Mark? Send it to email@example.com. Your identity will remain confidential.