Assalamu alaikum
There are different opinions across schools and between scholars regarding the acceptability of oral sex, so it's not a debate that has a clear-cut, definitive "yes" or "no" conclusion. Some people enjoy it, some people don't, and both perspectives are valid.
If this is something your husband doesn't want to do or have done in the bedroom, then he has the right to withdraw or withhold consent for it. Consent is essential and any person has the right to say "actually, I don't want to do this thing".
I'm assuming that your husband has concerns about the performance of such acts in both ways (that is, that he wouldn't want to be either giving or receiving) - if he's expecting to still receive it but not give it, then it could be worth reminding him that the views of most scholars don't seem to distinguish between women and men giving it. Consistency in practice is important, after all...
Even if this is something he's not comfortable with at the moment, there are still lots of ways in which you can both be close and enjoy each other. His views today may not always be his views in the days to come, too - people can explore different perspectives on things before finding what feels like the best 'fit' for them. Maybe you could explain to him that you absolutely support and respect his work on developing his faith and practice, and that you absolutely respect his right to give or not give consent to intimate activities, and at the same time, you hold a different opinion about the permissibility/acceptability of this type of intimacy. You could give him the names of a couple of scholars with whom you agree, so that he can read their views.