Let’s suppose the attribute set to split the cart is ‘Size’. Now add products to the cart. We can add two women tops with the same size and two men pullovers with the same size in the cart.

Click on View and Edit Cart, here the cart will be split into two. One cart having products with size XS and another having M size products.

Now the customer can make a choice as to which cart he wants to purchase and can proceed with checkout for that cart. The other cart will remain saved as it is in the cart.