BB cannot be used as a tool to "維繫感情". Actually, I have a baby about 5 and 1/2 months old. I think that if a couple's relationship is good before having a baby then it will be better after having a baby and vice versa.
Moreover, I don't agree that baby can help to "解悶" as taking care of a baby can make you exhaust especially if it is your first baby.
I am very positive about give birth of a baby as it makes us to have a better planning about our life. We didn't have much planning about our future before. During holidays, we just travelled around and found some good restaurants to have meals. Life was kind of without any "focus".
After I gave birth of my baby, I resigned and became a full-time mother. It is very enjoyful to see my baby grow-up day by day.
Just want to emphasis that I am not to say that a family must have a baby to make it complete. Also, it is totally wrong to say that not having a baby is selfish. Having a baby or not is totally depend on the couple's own judgement.
To both couples with or without baby, just enjoyment your marriage and have good time.