I'm no fan of marriage the institution but the results are clear. Policies that incentivize couples who would be married to not marry leads to worse outcomes for both parties at scale as well as any kids. It is regrettable that some may feel trapped in marriages that aren't working but the numbers don't lie. I don't want to make this a race thing because it's not but look at what happened to the urban blacks who had this kind of policy peddled hard at them starting in the 1960s. They regressed on tons of metrics that are closely tied to and both predict and are predicted by household stability. Your advocating for something that has been tried and failed.

(That said, perhaps the above would not be the case, or at least not to the same degree if women and men weren't treated differently with regard to child custody and men had the option of being single fathers)