Many relationships suffer from a wear and tear syndrome after a while. Add to it that there is a big age difference, his body image issues, his somewhat questionable attitude when you feel tired or when he is hurting your feelings, and you have a genuine issue here.
In addition to all of this, you are financially dependent on this guy, too, which is a major issue, too.
For whatever it may be worth, try talking to him again in a mature and factual way.
Start preparing for the worst case scenario, too. Look for a better job, network, and try to achieve a degree of financial independence ASAP. This is a matter of the utmost importance to you personally, regardless of the status of your relationship.
It is one thing to recognize that many people go through difficult stretches in life, and grow dependent on their significant others. And it is another thing to continue with the dependency without any viable plan to end it.
Unless you start moving away from being financially dependent on your partner you will start feeling trapped in this relationship, and the things will spiral out of control which is the worst case scenario, under the circumstances.