XP: Suggestions re DH and CIO

btsrc5

Every single night that DD had a little bit of a hard time going down to sleep, DH argues with me that I should let her "cry herself to sleep" so that "she will learn how to get herself to sleep."  

 He has not read one book (he isn't a big reader) or done any research on the subject, like I have.  I have told him countless times that babies are not able to soothe themselves and that letting them cry it out does not help them in any way.  

Do yall have any suggestions for me as to how to convince my husband that CIO is not an option, at all?  I am so sick of this argument!  Luckily at this point I am with her every night so I don't have to worry about him making her CIO at night, but I do worry that he will let her cry during the days he is watching her (which really upsets me just thinking about it).