as for wetness in the vagina i believe all the people answered you and your knowledge is quite ok. as for the fingering and so on, i beleive that it would be good for you to talk to your wife openly to see what you both like and dislike and get rid of feelings such as "I am afraid, it is not common" etc.
there is no limitation is sex and what make you and her feel good and it is acceptable to both of you it is ok and you shoudl do it. btw, ladies enjoy figering pretty much. just do it gently! and the key word is gently
as for G spot, first of all it is not a spot and it is an area.
location: abount few cm inside and up. you will feel that the G spot area texture is different than other places around. it is little bit more rough texture.
how to make her feel good: when you insert 1-2 fingers do the move of "come to me" while providing enough pressure to the G-Spot. some ladies like long movements, some like less and more pressure.
remeber that as Meirav said, women are complicated, not all women like or can get an orgasm from the g-spot. so be senstive and listen. may be your wife is a person who cum easier by her clitoris. BTW, some women are very much arouse in anal sex just because it pushes the G-Spot area from a different location. but as we know most women do not like anal at all
so, it is a quest of seek and find. beleive me it doe no take too long. this is why couples are getting bored with each other as the sex becoming predictable and therefore boring, but this is another story
lucky you that these days you have the internet to seek for advices for questions that are not being answered anywhere else in your world.
good luck!
