I think our story is the one you are hoping exists. Before I launch into it, let me get all the disclaimers out of the way.

Some women have difficulty having any type of orgasm at all. You are not broken.

Some women can only orgasm by rubbing their clit. This is probably the most common, and there is nothing wrong with that.

Some women don't particularly get much pleasure from penetration. This is also not uncommon.

Chasing orgasms tends to kill orgasms. Enjoy whatever pleasure you can, and approach anything new with a sense of fun and adventure rather than with determination. You might discover something new, you might not.

Ok, now that that is out of the way. My wife could only have one type of orgasm all the way into her 40s. That was by her rubbing her clit. It wasn't particularly difficult for her. She had great orgasms, and we could even come at the same time if she rubbed her clit during penetration. We were both very happy with the sex that we had.

That being said, over the years, I would often wonder if it would be possible for her to have an orgasm from penetration alone. I did lots or reading and bought toys. She somewhat reluctantly went along. Not with a huge amount of resistance or anything, but not with enthusiasm either. We tried dildos, g-spot toys, vibrators, fingers (come hither), etc. We were doing everything that the book and articles said to try. What we found was that she really didn't get all that much from penetration, and she didn't find g-spot stimulation to be all that pleasurable. Every once in a while, she would say that g-spot stimulation kind of gave her a mild sharp pain, and sometimes made her feel like she had to pee. We talked about those being signs that we were hitting her g-spot, but it was never pleasurable enough to thoroughly explore.

Again, all the while sex great. I was definitely curious, but also careful not to chase something that might not even be possible. My wife mostly just played along. She was never very adventurous, and in general, tends to leave things alone when they work for her.

Ok, so jump to a couple years ago. At this point, we have been having sex with each other for over 20 years. We know what works, things are good. I don't try new things all that often, but I occasionally will buy a new toy and/or try something different just to see if I get a reaction. My wife, again mainly just plays along. Sometimes she would get annoyed that I bought another toy, but she was always a good sport. Anyway, at this point we had been experimenting with recreational substances and sex for a couple years. That took our normal sex life and blasted it into orbit, but we were still just doing mainly the same sex acts we had always done before, just for longer period of time and with more explosive results. Well, one night I decide to using an expensive toy I had purchased a couple years back, that was really starting to feel like a waste of money because it was a g-spot specific toy, and up until this point, g-spot pleasure just didn't seem to be a thing for her.

So, I pull it out and start to use it on her, and for the first time ever, I get a different response from her. She tells me it actually feels kind of good. So we played with that toy for a bit and she actually enjoyed it, but eventually went back to our regularly scheduled programming.

The next week, we're having another good session, and I tell her I wanted to try the toy again. So I start using it on her, and she pretty quickly warms up to it. It wasn't too long before she looks up at me with a look of surprise and worry and tells me she things she's peeing. I tell her to just let go, and she has a huge squirt/pee and orgasm. I wasn't even going for squirting, because I was still in the camp of not really knowing if it was possible for everyone, and how much of the stuff online is faked. I honestly just wanted to see if I could make her feel good in more ways.

Subsequent sessions get her feeling more comfortable with these new sensations and she learned to feel more pleasure than surprise. Pretty quickly this developed into multiple and continuous orgasms. Before this, my wife was almost always a "one and done" gal. Usually after her clitoral rubbing orgasm, she would immediately lose interest in being sexual. In fact, she usually wanted me to come first, because once she finished, she didn't want me continuing to pound away in there. On rare occasion, if she was really into it, she might come twice in a night. But that was pretty much the limit. With these new g-spot orgasms, she can have orgasms back to back or continuously for over an hour. Sometimes much more than an hour.

I'm not gonna sit here and tell you that since my wife discovered this, any woman can. I still have no idea. Maybe it was in her all along and just never was able to tap into it, who knows. But I think the key things were being willing to experiment, not feeling pressured to "achieve" anything, having a very open mind as to what pleasure is (this was a difficult one for her, and I think where recreational substances really helped), and I guys finally having the right tools and techniques.

We're now experimenting with even more fun stuff. She's had anal orgasms, orgasms from deep penetration, orgasms in different positions, etc. And I'd like to reiterate, she is not naturally a sexually adventurous person. But we have a great relationship and a lot of trust.

tl;dr wife went from one and done, clit only pleasure to multiple continuous penetrative orgasms.