Your post stylizing is upside down. The thread title is to catch the audience while the thread body is to explain to the audience what the issue is.
Mind sharing the make and model of your headphones and the TV? Does the headphones work on your smart phone? To add, when using a headphone on a TV(pretty much any TV, the speakers get muted and the volume control on the TV manages the audio on the headphones(connected audio system).
There are some TV's that allow for management of audio in spite of having a headphone connected.
MERGED QUESTION Question from dkrootes : "Audio out for head phones"
I want to listen to TV at sensible volume while husband uses head phones at a louder volume ... the TV mutes using the head phone jack and no sound from the phones when using the video/audio out ... the only other audio out sockets is a digital audio out and the jacks on the earphones don't match ... it is a Hisense 39 in smart TV model 49P4 and RS 120 II sennheiser phones