It's clearly not CW's fault that her husband has a long-standing addiction to pornography, or that he has a long history of infidelity and sexual problems.
It IS CW's responsibility to make a decision about what she will tolerate and what she will not. There's an old saying that tells us that what we tolerate, we teach. One reason you can fairly say that "it takes two" is that even if the husband is doing and has done everything CW describes, she still has a choice as to what she will do.
CW, I'm not going to advise you to leave, although I will admit that reading between the lines, I feel like you're thinking along those lines and wondering if someone will tell you to do so. I'm not going to tell you to stay, either.
If you want to stay, there are some pieces of advice I will offer. Again, this is free advice from an anonymous stranger on the internet, guaranteed to be as reliable as that would indicate:
1. If you've found a sex therapist you think may be good, and he won't go, tell him you're going whether he does or not and then go. He may join you there eventually, or he may not, but that sex therapist can do a lot more for you even individually than we can do here on this internet forum. If you reach the end of what the sex therapist can do for an individual, and your husband still isn't joining you, then your therapist can probably at least refer you to an individual counselor.
2. From your description of what his exes told you, combined with your own experience, it's clear that this man has a history of serious sexual dysfunction. You may not be able to help him with that. You're going to have to be very clear about what you will and won't accept in your marriage. This means saying something like what Evolve suggested: "I love you, but I won't live in a sexless marriage with a man who can't or won't get help or help me fix the problem. If we can't work together to fix this, I have to leave you." Gotta mean it, though, because it's really possible you'll have to follow through.
3. I hope you saw the suggestion about safe sex above. As cold as this sounds, in your shoes, I wouldn't want to be taking any risk of becoming pregnant with this man's child. You may feel differently about that in a couple of years, but please don't take the chance right now. If that seems very presumptuous for someone who doesn't know you, that's only because it is, but you did ask for advice.
