It is completely unrelated to the merging of proposals...
Proposals that do not receive any activity whatsoever for over a month get cleaned out as a matter of routine maintenance.
"Domestic Life" had was created August 12th. By August 16th it had 3 followers; but not one new question, new comment, new follower, a vote, nor even and single edit since then (45 days). So it was nothing nefarious and nothing personal, just routine maintenance.
Feel free to re-create the proposal if you have reason to believe it will do better this time around. Situations change and people come across new resources and new ideas. But in terms of maintaining Area 51, I wouldn't like to see abandoned or stale proposals cited as a reason to close newer proposals made by people with renewed energy and, possibly, better resources to bring it to commitment.