My husband and I are busy and decided to keep our second son at his grandparents' for his first two years. Will this impact our relationship later?

You have two kids and you need to work out a system to handle both the children. Sending them to their grandparents is not recommended because no one can take the place of the parents. Believe me I know as I grew up with my grandmother. Although she loved and caref for me tremendously only I know how much I missed having my parents around. Plus you will miss out on all the wonderful moments of his growing up! What memories will you have to cherish?Why would you want to separate the two kids too? Bonding between the siblings will not take place either.Infact the younger one might feel jealous that his elder brother is more loved and that's why you sent him away . This will surely affect relationships. Take time to figure out how you can make some more time for your children. I'm sure that you will be able to find a solution. All the best.