I can't imagine my husband begging for it....but we are relatively new to this. I do think having my husband ingest the other man's seed has reinforced his submissive cuckold role....just like riding bareback had done the same for me. My pussy, his mouth....chemically bonded to my lovers bbc.
That's good that you have your husband lick it from you so that he ingests your lover's hormones, it may help make him more accepting of him along with the submission factor.
There has been some research regarding the effects of a husband's semen on their wives and it does appear that exposure to it via the vagina does elevate the wife's mood. While it remains to be seen as to if ingesting your lover's semen would have a similar effect on your husband, it certainly doesn't hurt to try.