Hello and welcome!
Glad that you are willing to give this a chance because your partner likes it. I think it's awesome, and hopefully you get to enjoy it too.
My partner did try it out too, she doesn't like it as much as I do, but she has been able to see why I like it and shares some of that. Which is great!
So, yeah, even if you end up not being able to enjoy it yourself, I think it's awesome that you try.
Anyway, I think I'd pretty much suggest what the user above said. Start by reading some vanilla, see if you like the art and maybe find it arousing. If you do, the next step would be to maybe read something about kinks that you have yourself in real life (maybe you are into femdom, or bdsm, or anal, or footjobs...).
Last, and only if you were able to enjoy these previous reads, I'd just explore and see some of the weirdest stuff (tentacles, monster girls, maybe loli...) I'm sure this is the stuff you've probably heard of and didn't like, cause it's the image most people have of hentai, sadly. Not because I don't like it myself, just because it's not the whole picture.
Hope you like it here!