The context was in response to an event that keeps reoccurring. For example, I bought a toy that I thought was cute. I liked it, but he was able to find a connotation that I did not know about, and said I bought it to be hurtful, because of that context. And like usual, I end up agreeing that I did it on purpose to hurt him. I hate myself for doing it, but it has been the only thing that stops the fight. I was also trying to tie in advice I received in response to another post, where there is a third option to agreeing to something that is not true, or trying to argue that it is not true - to ignore the details and respond to the emotions.
You could respond along the lines of... "
[name], I can see your point [reword his connotation] about the toy being used in a hurtful way that I did not think about and that was not my intent. Honestly, I bought it because I 'thought it was cute', and I didn't mean to hurt your feelings." This way you are validating his feelings without validating the invalid ('you intentionally hurt him' is invalid). You also implied an apology without making an actual apology with 'didn't mean to hurt your feelings'.
However, if he is still dysregulated, you can continue if you want with something along the lines of "
I can see that you are very upset over this, I want to apologize for making you upset. I can either put the toy away, for now, where it is out of sight and out of mind for now, [or I would even consider returning it if it upsets you that much]." In brackets [] portion only if you don't care to keep the toy. You are not apologizing for buying the toy, but rather making him upset because of some connotation you didn't think of. However, be mindful that he is disordered, and if this is a pattern that keeps 'reoccuring' it could be a pattern of abuse (controlling what you can and cannot buy, is a form of financial abuse), you need to discern this in your situation - if this is the case you would need to set a boundary on this.
Do not admit to deliberately hurting his feelings, he may use that against you in a future argument.
If he is religious, and the toy disparages his deity, moral code, or is offensive in any other way it is understandable. However, if it is something cute, that doesn't offend, see if there is a pattern of abuse. Alternatively, if you are buying the toy, and it is expensive, from joint funding, that can also be a legitimate issue, especially if your funding it tight.
I once had a talking doll, it was given to me as a 'gag' gift, the doll was a woman who looked like my wife, and was over the top making nagging statements on things my wife would say. [she received a similar one of a guy who looked like me making similar outrageous statements that were untrue of me] I thought it was cute and hilarious, my wife did not. I wound up keeping it, but my wife hated it. It finally was thrown away after the battery died on it and could not be replaced. I could see how my wife hated it, as it reminded her of something she didn't like in herself. While this is obvious, it can be a lot more subtle too, I like sci-fi/fantasy, my wife, not so much, so if I bought a toy in that genre, she might not like it. However, since she is miserly (her uOCPD side when baseline) she generally will question me on why I got it - so unless it is something I need to use for repairs around the home, or at my house of worship (where I volunteer), I don't get the toy (usually a tool, or piece of software), to avoid conflict - this is a form of walking on eggshells, that I myself am currently working on. My wife has gotten better with therapy, but there still are issues.
Hope that helps...
This can all be very stressful, make sure you do self-care whatever that looks like for you. (Even if it means hiding the 'cute toy' so you can enjoy it).
Take care with self-care.