Dr. Jacqueline B. Sallade offers ideas for maintaining your mental health.
People get remarried in their elder years and rarely share their finances evenly at that point, especially when there's a big discrepancy in assets or income, and heirs. Yet, that situation causes great stress when one partner starts expecting more inheritence or giving than the other partner originally agreed upon. One thinks it's unfair and the other feels used. I know several situations in which the house is owned by whoever bought it, not the couple together, and there may be arrangements made for the nonower to live there should the owner die, but the children inherit it. That seems right. But resentment can build, anyway. It's too bad and can undermine an otherwise good relationship.
My suggestion is that the person who is craving more money from the wealthier person should let it go, be kind and grateful for the lifestyle privileges which go along with their position, and realize that the spouse is more likely to be generous when there aren't greedy complaints.