My 5 month old has been self soothing himself to sleep for a month or so now. All of a sudden since…

My 5 month old has been self soothing himself to sleep for a month or so now. All of a sudden since Saturday all he wants is for or dad to put him to sleep, it’s exhausting and I dont get it. Has this happened to any of you? What could be the reason? I feel like now I have to backtrack and start over again. :(