to feel he should have told me about this health condition before we married

This thread shows why people with epilepsy don’t tell people. There is still a stigma isn’t there. How many other conditions would people not want to marry someone with.
As a parent of a young adult with controlled epilepsy the fear of something bad happening never leaves you.

If he understood it could be genetic and chose to have children with you, he absolutely should of told you. Otherwise, it would be a necessity IMO for a partner to have a full medical history including conditions that were no longer symptomatic.

I have to take extra folic acid as a result of my medication. It could be something similar with him so he was genuinely taking some sort of supplement as well. Doesn’t explain why his parents were monitoring it though.

My DH takes SV for bipolar disorder and they now say that men taking it during conception can lead to neurodevelopmental disorders in children. DH had only just been diagnosed and put on it when I got pregnant. DS13 is autistic and has mental health issues. Whether it's related or not I can't say.

OP, is sounds like you still have no idea whether is has epilesy or bi-polar or some other medicsl condition.

Let's be honest, you have no idea. He didn't disclose it then and he isn't disclosing it now.

You don't know who you have married and you can't trust him as he isn't honest with you.

It's not about whetner you would have stayed with him or not. For most people, epilesy isn't a reason to end a relationship. Bi-polar idn't necessary either but you would have certainly asked for more details.

I can't have kids. I told everyone I dated very early on, even though it's a heavy discussion for an early date. It's deception otherwise.

It seems complete wrong to me that lying about meducal conditions can invalidate insurance, lead to job loses but there's nothing in place to stop disclosing it to a spouse.

Incidentially, I know 5 people with epilesy, albeit none of them closely. None of them have an anger problem.

"Do I want to die with him beside me? Or do I want to die alone? How many more years do I myself have at 48, a few or many? Is it worth the pain and trouble? Should I do it on principle"

Sorry to be a bit blunt OP, but men tend to have shorter lives than women on the whole, so as he's older you'll probably not have him by your side anyway.
40s is an age when many people start reassessing their lives. I think you'd benefit from some counselling for you alone, there is a lot going on in there.
But 48 is not too old to split at all, and if you feel so strongly that he betrayed the younger you then you may have to split, if he's not prepared to acknowledge how you feel. It can take a long time for things to sink in sometimes. It's impossible to put the lid back on once you've had the realisation.
And that's without considering his short fuse etc.

There are plenty of people with epilepsy who:

a) Take their medication correctly, as adults
b) Are not neurodiverse
c) Tell prospective partners about it
d) Don't attribute personality traits (e.g. anger) to what is a neurological condition

There is a link between epilepsy and ND but that's not to say every person with epilepsy has autism/ADHD and every person with ADHD/autism has epilepsy. It's a % increase.

Sodium valporate shouldn't be taken by expectant mothers. I think (I may be wrong) while the same guidelines which restrict it's usage also impact men, it's actually got a statistically very low chance of causing any foetal damage.

https://www.nhs.uk/medicines/sodium-valproate/about-sodium-valproate/

For men taking sodium valproate, your fertility could be affected. It may also cause learning or behavioural problems in your child if your partner becomes pregnant while you're taking sodium valproate.

For men who could possibly have children, it's important to discuss sodium valproate with your doctor. You and your partner should use contraception while you're taking sodium valproate and for at least 3 months after stopping.
For men who are planning to start a family within the next year, speak to a doctor about your treatment options. Do not stop taking sodium valproate without speaking to a doctor first.

Are you in England? His full medical records will be on the NHS app. I can see my school age vaccinations on there!

It feels like you’ve come on here to get “permission” to leave. You don’t need permission—regardless of any of the backstory, he’s being a dick to you, and you’re allowed to leave. If that’s what you want.

@Arlanymor did you miss the part were the OP said her parents were strict Catholics? You're practically the generation below me and I would expect the nonsense to stop by then, but I'm just repeating what I heard around me from older people. There was a massive stigma.

I wonder it helps to separate out what’s actually relevant to the point you’re making. The epilepsy itself is one issue, and whether he should have disclosed it before marriage is a separate issue about trust in the relationship. But some of the other dynamics you mention, his temperament, conflict style, and his relationship with his parents, aren’t really explained by epilepsy. And I don’t think it’s fair or accurate to link those things directly to a medical condition, especially given he’s been seizure-free for many years and off medication for a long time. The fact his parents were involved in monitoring medication into adulthood sounds unusual, but that’s more about family boundaries and how they handled his condition, not epilepsy itself. I don’t think you’re wrong to feel angry about not being told something significant about his medical history. But it may help to keep that separate from assumptions about what caused his personality or behaviour, so you can judge each issue on its own merits. Does that make sense?

Is it because you feel responsible for your choices that you can’t/wont leave?

That is a very bizarre thing to lie about. And very odd that his parents were controlling his medication.

That’s not lying by omission—it’s outright lying—vitamins for gums?

Of course he should not have lied. This isn't new though so focus on what has changed and why this is key now. Definitely talk to a counsellor to work through your feelings as there is a lot to unpick.

Is he ND OP? Epilepsy and neurodivergence are highly comorbid. It juts made me wonder when you said he doesn't cope well with changes in plan, in still going to his parents for meds at 30, focussed on himself. difficulties with emotional regulation.....

Annulment has nothing to do with divorce or legalities, though. It's canon law - it has no effect on your civil status. You would need to divorce as well in order to remarry. But if you wanted to remarry in a Catholic church, you would need to get an annulment, which means a declaration that a valid sacramental marriage had never existed, because of a serious deception. Divorce legally ends a valid marriage in the eyes of the law. The two are different.

You ascribe your frankly mad decision to marry a man you barely knew to your parents' Catholicism meaning you 'weren't allowed' to live with him or go away with him. It's perfectly possible, from the information given, you are still a believing Catholic, therefore that you might want an annulment to allow you to marry again in church.

I agree with @BauhausOfEliott that you're hanging an awful lot on his epilepsy and his concealment of it.

I think you’re assuming his anger is related to a condition he no longer has. You can empathise with him but I don’t think you should be assuming it’s got anything to do with the fact he had seizures when he was younger.

Are you referring to the post about anger? That looks googled to me tbh but it’s sort of irrelevant. It’s not my experience. And your husband wasn’t being and isn’t being treated for epilepsy now anyway.