3) Took 18 years for my wife to admit to something that happened to her. Women are far more likely to experience negativity towards sex based on past experience.
7) Most women think sex is only about ejaculation for men which is far from the truth in marriage. Someone (a therapist) needs to convey that it is how you connect to her.
Bottom line - work on yourself before you try to bring her into therapy. Get counseling and quit begging or working so hard for sex.
I think your #3 example, past bad sexual experience, is so much more common than people realize. It's not just "rape" or some other type of molestation. When we're looking for something traumatizing, we probably make it worse when we think well, you must have had something terrible happen like you were raped, because you inadvertently make it seem like the only thing that could have traumatized her was being raped. Our MC was even convinced my wife must have been "raped" which threw her off the trail for some time. The woman who wasn't raped, at least by her definition, thus feels like whatever she went through, it must not have been that traumatic.
Bad early sexual experiences can include submitting, either willingly or by coercion, to sex that they instantly came to regret. Perhaps they became reactionary, for a short time, to their upbringing. Perhaps the sex itself was hugely disappointing and they saw that as evidence of punishment by guilt.
This type of thing may not come up through normal pre-marital discussions because they feel shameful about it. Matters are much, much worse if they didn't have a close friend to talk with about the experience. It never gets processed on a rational level, just raw emotions that could remain jagged pieces of glass each time she has sex in the future. Vaginismis could result.
I know nothing of this first-hand... no, nothing at all...
#7 is also very important. And again, this could be from early experience with sex, where in many cases maybe it was all about the guy getting off, and then it was over and he was gone. No long term cuddling afterward. Intimacy in marriage can be a very different thing, because sex when married is something shared only with your husband or wife. It's more than just a way to keep a partner interested in seeing you again. It's a connection to their soul. Or can be.
And the therapist. I'll bet most everyone who's been to a therapist has come to the realization they should have done it years previously. Get to it now. It will quite possibly make things worse for a while, before things get better. It's an investment in the forever thing.
And lastly- revisit your marriage, your vows, your promises and dreams to each other, a job review almost, on a regular basis. Stop being afraid to talk about where you are, what's disappointed you, what's been good.