KatyKube, you should go on the government benefit calculator and work out how much money from his salary your DH would have to contribute, by law, to your children's upkeep if he were to leave you. Then try and imagine running a home for you and your children. I imagine the quality of your lives would take a pretty dramatic nosedive. Do you work as well, or does your husband's job (and consequent contribution to mortgage, bills etc) mean you don't have to/can afford to be part time?
It really, really, REALLY isn't the same thing at all - so saying "I feel trapped too in my life" is fine, but saying you are "practically a single parent" is bloody ridiculous and no wonder you've been given a drubbing for it. Total lack of awareness of about 90% of the troubles single parents face specifically as single parents. Just as it would be annoying no doubt to you if someone said "my DS wakes up in the night, it's practically like having a disabled child", when you have experience of what that actually means and it is so much more than having to get up in the night.
Having said that, OP, you have one, teenage, presumably non-disabled/neurotypical child (unless there is a backstory here). You don't need to be there for him every evening - when I was 15 I spent very little time with my parents. What do you and DS do in the evenings together? What would you like to do instead?
You say in a later post you prefer not to bother - so what exactly is the problem? You aren't obliged to have a scintillating social life. If you are happy leaving it, then do. If you aren't, you are totally able to do something about it, at 15 he is practically an adult and doesn't need you to entertain him.