recently i've been feeling things were a bit off between me & my boyfriend. i tried mentioning it several times, to which he eventually finally told me. he said he lost the spark we used to have, that right now he's just kinda out of love. We've been dating for 4 years & we live together. idk what to do. has this happened to anyone before where their partner said they lost it?? i'm not even sure at this point if it would ever come back.