Marriage is not all flowers,roses and perfumed.Their are thorns too especially when babies come in.At that point,you discover that marriage is way different from a relationship.
When you were dating,their was no baby.. tension was almost non existent but with the baby comes a whole slew of responsibilities.You need to take care of the baby..baby food,baby clothes.. all the things the baby need does not come free.Bills start piling up..In addition,the wife pays more attention to the baby at this point..knowing the amount of laundry this little creature can generate is enough to drive a sane wife cray cray .
Well, you are still married and you guys need to weather the storm together.Going on a date once in a while wouldn't hurt because if you don't water the relationship, it will die.
Marriage requires work from both party and you need to both make sure that your marriage doesn't crash.
You may use the help of your mother in law to help in taking care of the baby while you guys go somewhere to mellow out.Goodluck