i think you are not clear what informed consent is. I think you also don’t understand risk either. Risks are absolutely not all equal. Risk is far more nuanced.
In the scenario you outlined the woman is absolutely informed about the lack of contraception that her partner is willing to use. She might not agree with his actions (or lack thereof) but she does know that he is not going to use condoms and has not had a vasectomy. She can then decide whether or not to have sex with him on the basis of that knowledge. If she still chooses to have sex with him, she has consented to sex within those terms- it is, therefore, informed consent. Obviously, coercion within an abusive relationship is a different thing- but then the issue is not deceit by her partner preventing her from making an informed decision, is it? the problem in that scenario is that the victim is not actually making the choice to have sex of her own free will. The issue is actually consent in and of itself.
In answer to your question, outside of rape and abusive/coercive relationships, if a woman’s partner will not use condoms or agree to a vasectomy- and assuming she does not want to be pregnant- she has a number of options, however unpalatable they might be. She can refuse to have any form of sexual contact with him if will not use a condom or has not had a vasectomy; she can refuse to have penetrative intercourse; or, she can end the relationship. If she does want to get pregnant and it is her partner who does not want to conceive, but he still refuses to use any form of contraception, then she still has choices. She can end the relationship; she can still refuse to have intercourse as he is being unreasonable; she can make him aware she is not going to be using contraception and if he wants to prevent a pregnancy it’s up to him to take appropriate action. If he fails to do that, it’s on him.
None of those things bear relation to a woman actively and deliberately choosing to tell her partner she is taking contraception when she is not. it’s a false conflation of two related but different issues.
With regards to your “risk is risk” statement, you are factually incorrect. It’s why Dr’s quote risk when seeking consent from patients prior to surgery or when weighing up treatment options. There are even things like absolute vs relative risks to consider. Risks are not all made equal. I suspect that you know this. People may be comfortable with a treatment with a small risk of serious complication but not with a much higher one. They consent based on understanding the risk they are taking. By your estimate all a dr would have to do is say the both option carry a risk of, say, death. Or loss of sight, or paralysis, or whatever, and not quantity the risk. Or not tell the patient that the effectiveness of one treatment is significantly greater than the other- because there is a risk of failure with both options. After all “risk is risk” right?
A more direct illustration of why relative risk is important and may change choices or behaviour (which is why being misinformed is so wrong) is chances of conception. Statistically, 90% of couples under 40 who are having regular unprotected intercourse will conceive within 12 months. If a woman has the contraceptive implant that drops to 0.02%. If she’s on the pill that would be 8% (allowing for real life effectiveness as the 98% technical effectiveness is reduced by imperfect use to around 92%). I can easily understand why a couple not wanting to conceive would be satisfied with the protection offered by LARC, or even the pill. Both parties would still have to accept that the possibility is not zero, but a 0.02% risk is tiny when compared to 90% if nothing is used. If you thought you were taking a 0.02% risk of an adverse event and later found you had been tricked into running a 90% risk of that adverse event (which happened), I think we’d all agree you would be right to feel aggrieved/betrayed/violated. If you can’t see that distinction, and the importance it plays in informed consent, you are either quite dense or deliberately obtuse.