You should not be doing so much in the first place. He is much older, with many kids, etc. etc., he has given you household responsibilities that you do not need to have, it is too much work. There is no balance of power in the relationship - all the work is on your shoulders. It is unfair to you.

You are not desperate. Do not act desperate then. There is too much drama, the kids are demanding or whatever it is that they are doing to you - why do you need all that?

Is it possible for you to move out and have a dating relationship with him instead? Why do you step in and help older men with household duties and child rearing? It is OK to date older men, no problem, but they should be able to make their own money, raise their own children, do their own laundry, and so on and so forth. And, deal with their children's mothers in such a way as to contain the rage and jealousy of said mothers so they do not spill onto the relationship with YOU.