If you are scared about your financial independence, then make yourself financially independent. Separate your finances from H's if that helps. Controlling his parenting choices is not the solution. Nor do I think his financial support of his daughter is the problem.
Rather, you seem to feel that H loves you less than his daughter. You equate financial changes with proving that isn't the case. This is a pretty unhealthy place to be.
First, people love their spouses and children. Getting into the who-loves-who-more-prove-it game is toxic. Quit playing that game.
Identify what you really want:
-- a stable, secure marriage -- feeling safe and loved -- assurance of financial security -- consistent reassurance of H's commitment to M
Figure out both by yourself and by working with your partner how to best achieve those things. Aim toward those positive outcomes. Drop vendettas and anger against SD. She is only 23, still very much a child. A young 23 year old woman fresh out of college is nothing like a 40 year old man with a PhD. Insisting there is no difference is not helpful. H still has more parenting work to do. If you try to squeeze out financial and emotional space for him to do so effectively, you are very directly harming yourself, your H, your M, and the children involved. And, even if you manage to get H to do what you want, it is not going to lead to what you really want, the sorts of things listed above.
On their face, your recent posts suggest a very dysfunctional longstanding family dynamic. Try to treat that dysfunction directly through family therapy rather than manipulating outcomes several steps away from the real problem. What you are doing with the rent issue is setting up a pass/fail test for H that likely seems controlling and manipulative to him. You probably know that already. So, even when he passes the test, it probably does little to reassure you. It sounds like H had little space or opportunity to demonstrate real change or show real concern, support and love for you. Without freedom and space, the opportunities for trust, respect, and love to grow are stifled.
Set yourself, your M, and your H up for success by finding positive ways to bring the things you want in your life.
