I suspect the wife is hiding some things in her chee bye.
Normal women will like oral sex done on her, if the giver is sensitive and smooth. Step by step from top to breast and finger her nice and slow.Massage her clit before digging her. From her bust down to her groin must be slow but steady.
When you are at the bottom , work on her inner thigh. Slowly work around the vagina and slowly kiss her vagina lightly. Then use your tongue to slither like a snake while you are using your hand to fondle her breast and nipple. Slowly intro your tongue inside the vagina, along with kissing and licking slowly on the outside then into the vagina with more frequency. Observe her reaction while your tongue is inside her vagina. She starts to get used to it
When she shows reaction on certain part, pay a little bit more attention. She will appreciate it. Then you ask her verbally which part of her vagina she likes to be licked most. Encouraged her to use her hands to widen up her vagina and let you lick. But of course don't rush when she tells you where she likes to be licked, so you just go slow and nimble her. Ask her to rotate her butt to your mouth where she likes to be licked more frequently than other parts. Make her be part of the process by asking her to move. She appreciate it.
After all sex is good. Sex is a union between man and women. It's a communion of mind and soul for each couple.