There's no problem here, unless it's the husbands.

She doesn't enjoy giving BJs anymore. It's not a sex act she likes, and it doesn't bring her intimacy with her husband.

That's the end of it there.

What she enjoyed before she met him is immaterial. The only reason anyone needs to give for not performing a sex act, is, "I don't want to do that."

That's it.

Hopefully the husband has no issue with either her lack of desire for a specific sex act (which is wholly her right to not want to do) or her past sexual history (which is hers and none of his business.)

If he does have an issue, it's his to work through.