My own experience has been far less doom and gloom in regards to sex. Communication is necessary with your spouse. I would say that she will certainly have less energy and attention for you. Though it is important that you both pay attention to your relationship and make time for each other.
I sometimes feel that with our generation we are trying to make up for, let’s say, the under parenting of the past. There were no car seats when I was a baby for instance. Dads especially were less involved. Children are important, but they shouldn’t be all consuming. It isn’t healthy for the kids or the parents. Make sure you take your wife or husband out on dates. Make sure that you show them you still care about them which involves an active sex life. Even if it isn’t at the same level of passion as when you were younger it is important.
Failing to do that is setting everyone up for failure. There are going to be challenges along the way. You will disagree on how to handle discipline and at times each of you will be short on patience. You need to make sure that you are in a good place with each other otherwise these things can spiral into bigger problems. While the husband may not be the center of attention for his wife and he should have reasonable expectations there, he can’t be forgotten either. Vice versa is also true. Make time for each other. Obviously you think that the other person is worth it or you wouldn’t be where you are.