DSL + LTE router connected to one PC. How to manage?

[Senzelian]

Hey guys,

I have a 2Mb DSL connection, which is obviously too slow.
Today I got a new LTE router to help me with my internet speeds.

Now I want to connect both routers with Cat5e cables to my PC.
One will be connected to my motherboard (ASUS Sabertooth S Z170) while the other one will be connected to a PCI-e network card.

My question is: How can I easily manage both connections?
I want to either combine both lines if possible or split them up so that I can for example play games on my DSL connection and download movies, music, games on my LTE connection.

 

Here is a very basic picture of what I want...

[Lurick]

I've never looked too far into how Windows does load-balancing on bridged connections but essentially beyond trying that and seeing how it works there isn't much else you can do short of some very advanced routing based on destination IP addresses which would require knowing the destination address of every game you want to route over the DLS connection.