"Just how uncoerced was sex for a wife in the Victorian era?

If we remove ONLY the conjugal obligation to provide "access," can we say that she has a choice? She still has no legal property which is hers to leave with. No legal status outside of wife ( unless the court annuls the marriage and reverts her to "daughter." )

Its no surprise that sexual emancipation requires legal enfranchisement, rights to own property, rights to leave at will, rights to work &tc."

Just how uncoerced was sex for a kept woman in Victorian era?
Fornication was not illegal in common law. An unmarried woman could not be legally punished for living with a man and having sex with him.

An unmarried woman or a widow living with an unwed man had the legal right to own her own property, leave him at will and seek employment. Employers were not legally forbidden to employ unchaste women.

Again have a look at Dolores. She did marry Richard Schiller in 1950s USA. She had the right to work, and did, as scullery maid.
The rights to refuse sex, leave home, gain employment if anyone would employ them and own property if they could save anything from their wages were something that unmarried women had always had in common law and divorcing or separating women gained in 19th century. Yet this did NOT give them sexual emancipation. For one thing, even though a woman with sufficient property was free to fornicate and bear children, few women owned enough property to raise children comfortably on their own. Leaving home and getting employed may have been perfectly legal, but if all they could get was underpaid menial servant jobs then marriage and sex was a good alternative even if she did not prefer it.
And for another, although it was not illegal for employers to employ unchaste women, it also was not illegal for them to refuse to employ or to fire unchaste women. The employment options of a known unchaste woman were even worse than the already limited employment options of a chaste maiden, wife or widow.

When did Dolores consent to sex?

Probably with Charlie Holmes. If she refused, or lost interest after the first few times, she would probably not have faced any dire consequences if she had returned to standing guard for Barbara Burke. While peer aged children commonly pressurize each other into sex - "Have sex with me, or you will be bullied for being a prude.", "Have sex with me, or you will be bullied because you do not have a boyfriend to protect you" - this does not seem to have been the case for Dolores. And if she had found sex not worth it, she would not have taken the initiative to seduce Humbert.

But Richard Schiller? Yes, she had an acceptable alternative. Continue as the scullery maid she already was. She had found it better than returning to Quilty, or returning to Humbert, or going to police and asking for foster care. But still, she never loved Richard the way she loved Quilty.

Was it consensual, if she was getting from Richard a slightly better living standard than independent scullery maid, and refusing sex with Richard would mean giving up being kept by him?