To expect people to be upfront with any ‘kinks’

The way he's left it so long, allowed you to get attached, discussed having DC with you, knows you don't have a lot of time, you've introduced him to your DPs, etc, feels very manipulative. I guess he knows that not many women will agree to whatever he 'feels he can't live without', so now he manipulates the woman into a position where she doesn't want to lose everything that the relationship represents, so is more likely to agree. Bleugh! Nothing more unattractive than a manipulator and god knows what else he's got hidden that he'll expect you to accept in future. I'd dump him. I'm sorry you're faced with this choice OP, but tbh if I was dating now I'd be upfront, right from day one, that if you've got some kink you're not for me.

But I'm confused that you say that you'll do it, 'of course'. There is no 'of course' about it! You should never feel manipulated into anything that you don't want to and quite honestly, if you're prepared to do this, you need to take a long hard look at your boundaries.

If you are kinky, it’s never been easier to find someone with whom you can be upfront.

You want to ask what it was that makes this man put such importance on this but not tell you. Common sense would indicate he waited because you would have an emotional connection, you would actively listen, and you would think about changing something about yourself. That is very manipulative and only benefits him.

That little instinct that made you post will go away if you decide his needs are greater than yours. Then he will be in charge of your relationship. This is likely a start, not an end.

Silly to say you wish you'd known sooner so easier to leave, then moan about it and say you'll do it occasionally "of course."

Frankly, I'd expect deal breakers (including kinks) to be discussed by the fourth date, not the fourth month! What's the point in dragging it out for four months, when you could've found out three months earlier that you were completely incompatible? Who wants to waste that kind of time? I say be up front about major deal breakers on the third date - that way if you're compatible, you can go shag to celebrate, and if you're not, you can part ways without wasting time.

I think it depends what the kink is/whether they might reasonably have expected you to be on board with it. Though 8 months is quite a long time to go before mentioning something that is apparently essential.

I find the timing of his revelation to be very manipulative. If this "kink" is a dealbreaker then it should have been discussed much earlier.

Doesn't bode well.

You can't possibly consider children with him for the forseeable. You barely know him. He has just sprung one surprise on you. There could be more that he is hiding.

He's deliberately chosen this moment, when he thinks you are attached to him, when you've just introduced him to family, to tell you a fundamental and potentially deal breaking aspect of himself. That's manipulative and a terrible start to a relationship. If nothing else, it shows that he puts his needs first and you will always be second to him and his kink.

If time isn't on your side, don't waste any more of it on this one. You will only live to regret it.

Not knowing what these things are makes it really difficult to judge how out of the ordinary they are. One persons making things more interesting is another persons no way. If it's threesomes or swinging it would be not a chance. If they are things the op just wouldn't do then it's time to let him go whatever they are. He won't be happy if she refuses and it will be a problem between them forever.

What on earth does being open-minded have to do with one's personal sexual preferences?

And no, OP, you're not unreasonable. It's just a waste of everyone's time and feelings if one person has a kink they 'need' to indulge, and doesn't tell the other person up front.

I know it's not exactly in the spirit of MN, but I'd give him the benefit of the doubt. It can be really difficult to talk about sexual preferences and kinks, and like a PP has said, people are between a rock and a hard place when it comes to choosing when to share their preferences with a partner. It's likely he needed to build up a trusting relationship first, within which he could feel confident he wasn't going to be shamed. It's also hard to know where you sit on the vanilla-kinkyasfuck spectrum so maybe his comment about PPs is part of him trying to weigh up how others have felt about it, versus his own shame about his kink. I can see how some of the language OP has shared could seem manipulated, but I also think this is him laying his cards on the table in terms of it being a non-negotiable, which is surely better than him minimising the importance of it now, then it turning out to be a bigger deal further down the line.
OP, if you can, respond with curiosity to his kink - ask questions without judgement about what it involves and what he would ideally like it to look like in your relationship. Then make a decision about whether it's something you can be on board with.

I really think that some men enjoy “changing” women to integrate kinks into a relationship. Obviously it is easier than ever to find someone like minded and willing, so this type of guy, who is basically dishonest, is someone to get rid off.

I told my partner my kinks early on. No issues.

This is such a weird interpretation of events. No one wants someone to bring their kinks up on a first date (which OP herself has said). Obviously you wait until you're sure someone likes you before you bring up something that makes you vulnerable? It's a question of trust, from his perspective.

Notice how the women who had “no issues with it” are all Ex’s.
Sex preferences need to be discussed when sex first starts in the relationship.
His waiting for the family introduction is no accident.

Very odd timing to ask you on the same evening he had just met your parents…

None of that is manipulative. It's putting his cards on the table. OP is free to walk away (and if she's not into this kink then she should).

I'd get rid, OP. He's manipulative. He's waited until he knew you really liked him and saw a future with him, then threw this into the mix. He could have told you it before sleeping with you the first time, but chose not to. Every day of those eight months have involved him making a decision not to tell you.

I'm dying to know what it is!

Anyone prioritising some kink above actual relationship isn’t going to be for you anyway

He has to decide whether he wants continue the relationship or chase his kink. Don’t do anything that you don’t feel comfortable doing. I agree that he should have discussed this much earlier in the relationship.
Kinks vary widely, I’d base my feelings off what the kink is.

No coincidence that the same evening he’s met your parents, he brings it up. Whatever it is, that would be enough for me. Devious. Sorry you got to eight months and he met your parents 😔

Yeah I'd say 2-3 months is the right time to reveal this kind of thing, when you're comfortable with each other and have been having sex for a while.