Best dildo?

Alright guys..29 year old woman here who has never owned a dildo.

I feel like i am at the peak of my sexuality and I do not get the sex i need from my partner. He is a once a week type of guy..who is pretty vanilla. He also does not go down on me. We been together for years and he used to all of the time but as he has gotten older..i just don't think he is any good at it and thats why he doesnt. It really does not bother me that he doesnt...because its never been all that great for me.

I want a dildo. He would be FURIOUS if he knew that I had one but dang..i just got to.

What are the best ones? My bf is very big down there...so it needs to be thick and at least 8 in(sorry guys...tmi)..? And im not into anything crazy( not into ribbed...shapes.. Ect)...but I wouldnt mind some vibration.

Help a woman out