What would probably happen is that any of the beta males you refused to have sex with might just rape you if they got half the chance, and you would therefore rely on the men who you do want to have sex with to protect you from being raped by the ones you don't want to have sex with.
When you got too old to be sexually interesting to the men, you would be just cast aside.
Under a patriarchal system of monogamy, you and your husband would just have each other, but you would have children who would look after you in your old age.
Although you would still produce offspring by various men under the matriarchal system, it is less likely that these children would look after you because, once these men stopped fancying you and transferred their attention to a younger and more attractive female, they just wouldn't bother telling their children to look after you.
Under a patriarchy, both parents would exert equal influence over their children, which means their children are more likely to love them and look after them in old age.
Because under the patriarchal system men and women would live longer and be respected and looked after more, more knowledge and wisdom would be passed on than under the matriarchal system.
Under the matriarchal system, life for men would also be brutish and short and would end when they got old and frail, because the children they sired would have no particular loyalty to them either. No man would really be sure which child belonged to them and their emotional investment in a child who may just be their offspring would be low and their children would feel no particular connection to them. There would not be much natural feeling of the affection a parent and child would feel for each other under the patriarchal system.
This was how marriage first worked to improve the quality of human relationships and maintain the transmission of knowledge from one generation to the next.
Once we return to the old system of allowing woman to have sex with whoever they pleased, we will go back to the old system of human relationships.
Now, those of you who keep saying that marriage is just a piece of paper, which system do you prefer and which system is to be preferred if you care about preserving the existence and health of your civilisation?