I'm still a bit unclear on what you want this money to ultimately be used for.
You mentioned 3 years and quitting your job in May. Are you planning on using this money to support yourself during this time? Do you have other cash-savings (an ER fund)? Can you live on DH's salary alone? What happens in 3 years?
Broadly speaking, I would say that you should keep any money you think you will need in the next couple of years in a savings account. Anything beyond that should be invested, starting first with tax-advantaged accounts.