Strict Wife

This does sound borderline abusive or, at the very least, obsessive.

Have you and your wife been through any parenting classes? Those might help, or at least a talk with your pediatrician. A treat every now and then should be fine for most children - I am not a doctor but I am also not seeing anything in your post about obesity, diabetes, etc.

we did take a basic parenting course but it wasnt anything extensive. She is a very healthy 3 year old. No reason at all she cant have a treat now and then.

We had the rule that our daughter should not have any chocolate or sweets until she was two years old. Exceptions were birthdays and other invitations.
When shopping, she, like most other children, strechted her small arms after something eatable in a bright colour. So I started to buy a small bag with small
cheeses with a red cover, She just loved them.
Later she was allowed "Saturday treats". This meant she and I went to the store and bought some treats. Nothing else. A special fun just for her. Not much, but still. She could eat it all on the way home or save and have for the rest of the week. Her choise.
She was a healthy girl, her teeth in perfect condition.

My wife is afraid of everything. She cant stay home alone if im gone overnight for work. The other day I got a text from her. She was in the driveway and afraid to get out of her car because there was a cat in the yard. So I come outside and It was a Kitten. She couldnt get out of her car.......a kitten. So I go get my 3 year daughter to see the kitten. It was a clean, white, very friendly kitten. I let my daughter pet it and my wife FLIPS out. She thinks the cat is dirty and diseased and will infect my daughter. After a fight, I proceeded to allow her to pet the cat then my wife sanitized her. Not only did she believe she was going to get infected, she was satisfied with wetting her hair (because she touched her hair after petting the cat) to sanitize her.

I am not a doctor, but it sounds like your wife needs medical attention from a competent therapist or a psychologist.

Please at least get her to her primary care physician so you can discuss overall health concerns and see if you (yes, you - please go with your wife) can get it out in the open about how your wife is behaving.

How do I tell her I think she needs to see a therapist when she thinks she is completely normal?

Don't say that - frame it that you want her to see her primary care physician. If she balks, then frame it as taking your daughter to the pediatrician.

Take time off from work if you have to, but make certain you are a part of this.

You cannot get her to a psychologist without her agreeing.
Go to your doctor alone - yes behind her back - have a serious talk with him.
Then you both go there for a yearly check up/ or whatever and then it is up to the doctor to ask questions and find out more about the situation and send her to whatever he feels would be the right thing.
For your sake of your daughter - do something. If grandmother is like that
and mother - the daughter probably also will be afraid of everything as she learns from her mother.
Still it is not too late to do something.

right, but medical docs are out of the question. She never sees a doctor. She would go to ER for an emergency but thats it. She had our kids with a midwife (which I agreed with) She wont go to a doctor though. Never.

Does she take the kids to check ups at the doctor? And how about dentist?
If she never sees a doctor and the kids neither and top of it she is afraid of
evertything - you really have a big problem.
You better see a doctor and or a psychologist, who can help you. This is close to
being abusive.

Are you afraid of divorce? If your wife is abusive, divorce might be the best thing for your daughter. This is a clearly an issue that is bothering you, and it is clearly a way that the marriage is not working.

My advice would be to get marriage counseling. You can insist on your wife going, or make it clear that the marriage depends on it. A good marriage counselor can work through setting reasonable limits and provide a way for you and her to work together as equals. This would also help you listen and work through your wife's feelings with the help of a counselor.

You might also see if you can get a counselor to work with your daughter.

my only fear in divorce is that she would get custody of the kids. I cant be without my kids.

she has agreed to marriage counciling! This is big! I feel better already.

That is good news. Good luck!

If you need a divorce in the future (and obviously this is not always the best thing), you should know that in many places fathers can get equal custody of their children. If you choose to go this route, it is important that you act responsibly... and are seen to act responsibly... since a judge will decide about custody. You can talk to a lawyer about this.

I had a similar situation; my ex-wife was far stricter than I. I now have 50% custody of my daughter. It turned out to be the best situation for all three of us.

My ex-wife and I have learned to co-operate on most things now that we are divorced... but the things we don't agree about are resolved by the parenting agreement. When my daughter is with mom, she follows mom's rules. When she is with dad, she follows dad's rules. For us, this has worked pretty well.