Cannot record using cable splitter

I am using Elements version 10.5.12 build 123, built Feb 12 2020. I also have Realtek Audio installed (Audio Driver Version, UI Version

I have only one port for my audio jack on my laptop. I can connect my headphones or my microphone. They work fine on their own, selecting ‘headphones’ or ‘mic in’ respectively as the appropriate Connector from the Realtek Audio Console. However, I want to use both simultaneously, so I bought a cable splitter.

I now connect both headphones and microphone to the splitter and connect the splitter to my laptop. I select ‘Headset’ as the Connector. Sounds captured on the microphone I can hear clearly through my headphones. However, I am not able to record any sounds. It is as if the sounds bypass Cubase.

Under VST Audio System, I have selected ‘Generic Low Latency ASIO Driver’ as the only option I have. Under Audio Connections - Inputs, I have as an input bus, ‘Mono In’, with Microphone Array (Realtek® 1 selected as Device Port. This is selected as the input for the audio track on which I am trying to record. Again, recording works fine if I connect only the microphone directly to the laptop.

Any suggestions as to how I might investigate this problem in more detail would be most gratefully received.

It looks like a limitation of your laptop I would look into getting a usb audio interface device . They vary from cheap to very expensive depending on your needs

Thank you, I shall look into this.