Yeah, foreplay is hugely important.
I also recommend the book "hot sex" to really lay things out and look at it from several different vantage points.
Also having been raised in a fundamental baptist household where sex has a very rigidly defined purpose and outside of marriage is sinful, I can tell you that it really weighs on your psyche. I'm guessing you're well aware of that since I recall you saying that you are or were christian. And my current girlfriend who is quite the nymph still struggles with guilt to this day. I certainly did until I started eradicating my limiting beliefs, but I had to wipe Judeo Christianity from my mind as a possibility before I could fully immerse myself in the sexual experience.
The mind/psyche is a huge part of sexual relations, and controls a lot of the body's biochemical processes. So if she's not getting wet, I would start with the mind. Really have her flesh out her feelings about sex. Have her write them down and try to determine if there are any unhealthy beliefs contained within. We are sexual creatures, all creatures are (with some exception of course! black tip sharks, et al), sex is a gift and a good and wonderful thing. It is pleasurable, life affirming, and from our point of view, really doesn't involve disease as long as all parties are living heathfully (proper foods, healthy minds). To see it as something 'other', or sinful, or private is, if you look closely at history, simply a product of human reason/belief systems getting in the way and seeking to control people.
I cannot recommend that book enough. Ejaculation/orgasm should not be the end goal. The whole entire experience from the anticipation all the way through should be viewed equally importantly. You should be able to spend hours on occasions in touching and kissing and massages, oral and manual stimulation, with toys and role play, etc. It should be an adventure each time, and it only ever grows old if you approach it the same way on every occasion.
Being relaxed is a huge part of it too, stress can absolutely murder the experience. Massages, aromatherapy, mood lighting, and perhaps a little meditation (breathing out the worries and daily responsibilities) can be all it takes to make the experience a good one.
Can we assume you're both sexually attracted to eachother? I've dated girls who I could have fun with and be best friends with but was not attracted to, and that does not exactly facilitate arousal!
Also don't focus on this problem in the sense that you're stressing out about it, you will give it power. Instead, seek to remedy it, but in the mean time, just use a natural lubricant and keep her well lubed up, lubrication will make or break the experience, the difference between smooth gliding and sandpaper (which may be uncomfortable for us fellas, but is pure hell for the ladies).
Try bringing her to orgasm several times manually or orally before actual intercourse. Or try bringing her to orgasm first, then a short period of penetration then back to manual/and or oral. She can use a vibrator on her clitoris during penetration as well, this will help immensely with the added bonus that she'll probably experience multiple orgasms and perhaps female ejaculation. However try not to become dependent on this, it should be used for augmentation, not the center of the experience.
Women are incredibly sexual creatures, I'd say more than even us fellas, which maybe runs contrary to popular opinion, maybe not. And though I do believe our modern day habits of harried schedules, ubiquitous vectors of toxicity and religious dogma/societal mores have a huge impact on both sex's libito, I would not say women specifically are less sexual than their forebears.
Good luck, and that book can be found on audiobook (a pleasure to listen to) via torrent or purchased obviously.
