I've been wrapping my mind around this question for some time now. What makes it so complex for me is that you, Chammpi have given so little context.
How do I tell him that I don't like oral sex anymore without hurting his feelings... and I fear that he will go for other women if I reject oral sex
IMO, it all boils down to two questions:
(1) how realistic is this expectation (that he will seek a new oral-sex-provider) ?
and closely related...
(2) if he did - what effects would that have on you?
(1) As long as your husband doesn't know that you dislike giving oral sex to him, he has no cue to change or seek resolution together with you.
In my personal definition, a "good husband" would be at least concerned if he knew that his wife does something she strongly dislikes; he would then try to find a good solution for both of them, plus he would encourage more openness in all aspects to forming the relationship in a way it fits to the needs of both partners.
I am well aware though that there are different definitions of a "good husband", specially in contexts with high social pressure being put on young people to succeed as wife / husband, and the absence of options to design the relationship or get divorced. This is especially true if someone else chose that person for you and arranged that marriage with you having little or no say in this.
(2) As others have noted, if oral sex is an essential part of your relationship, and your husband is likely to ignore your needs, and you are really dependent on this marriage, then there is a different perspective.
In this case, I would like to motivate you to reduce your dependency on this marriage. I frankly do not know if and to what extent this is possible for you, I certainly wish it is.
If you would choose that path, "optimizing" the act itself (making it less troubling for you) might be the way to go, until you are in the position to stop doing it.
In strategic marital counselling there are strategies applied to influence the partner's behaviour by changing own behaviour, if the partner does not come to the counselling sessions, talking about it is not an option (yet), and the issue is putting damage on one partner.
These strategies do not involve talking about it, but altering the underlying structure of the interaction in ways that make it less desirable - see example.
The information given in the question is too vague though to suggest a specific strategy.