There are dozens, if not hundreds, of sites that "explain" the differences between these two. But after reading so many I am fairly convinced that there is no actual definition, at least not that I have found, feel free to correct me. It really seems to come down to attitude and intent. The best I can tell there is a LOT of cross-over between the two.
A woman is sometimes considered a "Hotwife" or "Slut-wife" when she enjoys sex with people other than her husband, she is looking for more sex. It seems that the Cuckoldress most often has additional partner for quality reasons. Her husband is inadequate for a variety of different reasons. It seems that the relationship between the cuckoldress and her husband is often one of dominance and humiliation. Interestingly it seems that whether the woman is a Hotwife or a Cuckoldress the husband is usually referred to as a cuckold. This may be why it is so hard to find consistent definitions.
There appears to be somethings that are shared between the sub-types. Most men interested in this kind of relationship or lifestyle (depending on how far they want to take it) seem to be quite intelligent and most often pretty successful. The other thing that appears to be true is that most Cuckolds seem to be very monogamous. When this type of relationship or lifestyle first is first suggested the wife often assumes that their husband is setting a "trap" in which, once the wife starts having sex with other men, the husband will be free to have sex with other women. I have no pages that suggest that this is the case.
Although this term may not be correct, I have found that there are a number of husbands that ARE dominate. Usually the female in this relationship is a Hotwife or Slut-wife. These men often seem to do the actual arrangements for their spouse. They post the ads or interview the prospective lovers. Most often from what I have read these guys are voyeurs and rarely do their Hotwives play alone, nor do these men usually participate in cream pies or clean ups. When they play with the wife and her lover it is usually in MFM where the men have little or no contact. Although it appears there is a lot of cross-over between the cuckold sub-types, the Dominate Cuckold seems to cross over the least.
The Submissive Cuckold's partner seems to be a Hotwife as often as she is a Cuckoldress. This cuckold sub-type's primary concern is the pleasure of his wife. Although he may not derive pleasure for himself by being submissive he often does. He enjoys hearing of her experiences, he helps her dress for her dates and often refers to her lovers as Bulls. He may let his wife and/or her lover to direct his actions for the purpose of sex or to help them enjoy themselves more. He may stand patiently near them during their session waiting for direction.
The Bi Cuckold likes to participate with his Hotwife/Cuckoldress and her lover/Bull especially in an MMF threesome. He often enjoys the cream pie clean up. He may have chosen to be in this type of relationship in order to have access to sexual contact with another guy without needing to admit or be labeled as "bisexual" or gay. He likes to have contact with both her lover and her lover. It may be as simple and discrete as guiding her lover's cock into her pussy or as overt as performing oral sex or allowing her lover/Bull to penetrate him anally. There is something sexy about "fluffing" your spouses lover for round two.
This sub-type may be the most broad as it is kind of a catch-all. It seems to range from guys who get please from knowing their Hotwife/Cuckoldress' lover/Bull has a larger penis all the way to husbands who like to wear women's clothing and cock cages. I really can't speak to this a lot because it is what I have probably read the least about. Cross dressing and chastity are definately not my thing.