Women rarely marry DOWN the socioeconomic ladder. It is women at the top who actually have a seriously limited pool of men to partner with.
A woman at the bottom, can benefit from partnering with just about any man who is actually planing to even try.
THe magic of sharing rent is an obvious benefit, even if the guy has some issues.
As long as both are sharing rent. It's the whole trying part. Plans are a dime a dozen and is usually the problem; it's the follow through that counts.
Women don't marry down the ladder despite the romance novels of the blue collar worker meets wealthy heiress/journalist/rancher/CEO/financial adviser. It's not the norm. I agree. However, the odds of a woman working the register at a local convenience store meeting, falling in love and marrying the banker are slim to none. So, they are dating whomever is in their community.
The point being that many women picked up the pieces from whatever relationship they had and either created the opportunity or obtained work to provide housing, food for the children that they had. Same as they do now. I don't care what time frame we are talking about because curling up in a fetal position has traditionally not been an option.