Car just quit working it died everything stopped?

I was driving one day and all of a sudden my car just quit working it died everything stopped on it and I had to pull into a parking lot and it would not start back up. We checked all of the fuses and all good. The fuel pump relay is not getting power. Cleaned all ground contacts and replace ECM still no start. I was told that the fuel pump is probably weak and therefore not sending power enough to the fuel pump relay so I replaced the fuel pump and nothing changed I even put in a new relay for the fuel pump relay nothing it'll try to start and that's it and it's but it doesn't start. I ended up taking some wires and bypassing the fuel pump relay with the toggle switch and that works it allows me to start my car drive it normally. My check engine light is on now for my oxygen sensors so I don't know if that has anything to do with it or not but I am out of answers or theories for this. I don't know what else to even look at to diagnose why it's not starting cuz when I turn on the toggle switch to ignite the gas fuel pump it starts up it drives just fine when I turn the toggle switch off it will just die on me but there's not very much power getting to the fuel pump relay any ideas on what else to do and how to diagnose this because like I said I have cleaned all the grounds replaced the ECM and everything but nothing all the fuses are fine all the relays are fine