Banished citizens don't marry and/or split up

I'm on my second attempt trying to lead the poor people to success. My first village died off from old age, this time everything is just perfect. Except for one thing: My villagers hate each other. How come that I have so many people living alone? I'm 28/10/11. In theory I have enough houses for every adult to pair up, but every house is occupied and far from optimally. There are many singles in their 40's and 50's. Females and males alike. No deaths from old age or accidents have occured yet; I'm in my 8th summer. So how do this happen? I've seen it in both my games.

So what I would like to understand: Why are there people living alone when 1) nobody has died 2) there are opposite sex in their age group also living alone

I even have young people living alone (ages 20-30) and plenty of young people of both sex just refusing to leave their parents' home.

I have spread homes around all workspaces nicely so there are more homes than jobs in any one location. Some of the singles have children!! (below 10)

EDIT

I just experienced one of my citizens becoming homeless. How does this happen? I made no deletions. He is 31 years old and idling pretty far from his job, very happy and very healthy.

EDIT #2

He got stuck in an unescapable place behind some of my buildings (the buildings are very old, so somehow he got teleported there and he was just registered as homeless, apparantly, when he couldn't get back out) I'm gonna let him freeze to death rather than deleting my house.

I've built 2 houses. They've stood empty for at least a minute of gameplay. Many of my houses are full of young students of all sexes. Whay is happening?

Solution 1:

You've built too many houses too early.

You should only build houses when you have adult children of both sexes still living with their parents*. When you then build a new house, two of them will form a couple and move in together.

When there is an empty house, an adult living with their parents, but no potential partner in the same situation, they will move into that house alone. This happens when you have empty houses available and children turn adult or you only have adult children of only one sex.

Once a citizen experienced the joy of living a single lifestyle, they will be single for life. They will never let a partner move in with them.

But note that women bear children even when not living with a husband. So having lots of single-households doesn't hamper your population growth - it just wastes space and resources.

*) I am not sure if they need to live in different houses, of if it is possible for siblings to form an incestuous couple.