This moment, captured in time, is proof of unwavering affirmation that she is his hotwife and he is her cuckold. If we could see a wider view, I’m sure we’d see a very erect penis, likely glistening with cuckold tears – but not because he’s so enamored with her boyfriend’s semen. This is a common misconception perpetuated by fake and unrealistic ‘cuckold porn’ and by the gays/bisexuals hiding behind the lifestyle’s practices. 
More succinctly; ‘creampie’ isn’t meant to be about the pie it’s about how it got there.
The only heterosexual reason to desire this expression of love between hotwife and cuckold is as an expression of love, submission and undeniable affirmation. There is also no requirement that a cuckold ever perform this act and if he does, there’s no rule that says he can’t first clean his wife first with a warm, damp towel before applying a soothing tongue to her swollen sex. The true purpose of this act, in my opinion, isn’t the exposure to or consumption of her boyfriend’s semen, but to provide an intimate pleasure both because and despite her having coupled with someone other than her husband.
Update: A discussion in the chatroom with @newbycuck produced this concise thought regarding this topic: when a cuckold desires the substance more than he desires the act, I have to call ‘orientation challenged’.
I love it, nothing better. It is me showing my wife I love her and accept her and accept my giving her to her lover, acceptance of his cream in her is the ultimate humiliation for me. It is also telling them both that I am his and her submissive and I accept his ownership of her (us) without prejudice.
It is an expression of shared intimacy. The cuckold is saying that his is part of it all. He has helped deliver the pleasure she just experienced through his unwaivering consent. It is an act of completion, and he is not there to clean up something defiled, but to affirm that his wife is acceptable and exactly in a state that deserves his attention and unashamed adoration.
For me it would be to show her how much you still love and adore her.
To show her that she could never be tainted to you No matter how many men she is with.
No matter what she does with them. You are still there as always waiting to pleasure her.
I would agree. I believe the ultimate goal of the cuckold is to support and encourage the wife for her own pleasure and satisfaction. The cuckold deriving his pleasure from hers.