I worry that your boyfriend feels that he will lose his relationship with his kids if he starts requiring them to be more responsible at home. The kids need him to be a father, not a buddy. Few teenagers like to be told to clean up their messes. But our job as parents is to teach them and civilize them in spite of protests. I’m sure he wants them to be able to function as adults and to be able to have loving relationships someday. To do that, they need to learn to do their share in maintaining a household.
It sounds like their mother has essentially abandoned them and their father has been overcompensating by demanding very little of them. The kids may see you as trying to take their mom’s place, even if that isn’t your intention. They may blame you if their dad starts making reasonable demands. Both you and their dad need to help them understand that no one can take their mom’s place but that you can still be an important adult presence in their lives. Their dad needs to apologize to them for not teaching them how to be contributing members of a home and then to insist on some changes.
It is not okay for you to be the unpaid custodial staff for his kids – and it’s frankly not good for any of you. If he loves you, it’s also not okay for him to ask you to like it or leave. Part of becoming a couple is negotiating how your life will be together. As you talk about what each of you needs and what family life should be like, you will also be figuring out how the two of you work out differences. That’s an important developmental stage for any couple. Once the two of you decide together what would make you both comfortable in terms of level of cleanliness, how chores are done, and who should do them, you will also need to figure out how to be a team and get all the kids on board.
I really, really hope that you and your boyfriend love each other enough to work on blending your families. If you can pull it off, everyone will benefit — even the teenagers who don’t think so at the time.
I wish you well.