As others have mentioned, there are likely multiple things at play here, and the toy collecting has become the symbol of everything that's wrong with the relationship.
That being said, addiction takes many forms, and you may need to ask yourself whether your collecting habits meet the general definition - or at least the spirit of it. Take a look at the DSM definition of addiction aka substance dependence. Just because it's not booze, drugs, or food, doesn't mean you aren't exhibiting these symptoms where collecting is concerned.
Addiction (termed substance dependence by the American Psychiatric Association) is
defined as a maladaptive pattern of substance use leading to clinically significant impairment
or distress, as manifested by three (or more) of the following, occurring any time in the same
1. Tolerance, as defined by either of the following:
(a) A need for markedly increased amounts of the substance to achieve intoxication or
the desired effect
(b) Markedly diminished effect with continued use of the same amount of the substance.
2. Withdrawal, as manifested by either of the following:
(a) The characteristic withdrawal syndrome for the substance
(b) The same (or closely related) substance is taken to relieve or avoid withdrawal
3. The substance is often taken in larger amounts or over a longer period than intended.
4. There is a persistent desire or unsuccessful efforts to cut down or control substance use.
5. A great deal of time is spent in activities necessary to obtain the substance (such as
visiting multiple doctors or driving long distances), use the substance (for example,
chain-smoking), or recover from its effects.
6. Important social, occupational, or recreational activities are given up or reduced because
of substance use.
7. The substance use is continued despite knowledge of having a persistent physical or
psychological problem that is likely to have been caused or exacerbated by the
substance (for example, current cocaine use despite recognition of cocaine-induced
depression or continued drinking despite recognition that an ulcer was made worse by
Honestly, I'd suggest many of us may exhibit some of these symptoms (I recognize that I do). There are organizations out there such as Celebrate Recovery that address all forms of addiction (not just the big two), and they can give you the tools to address it if you feel it would help.
I'm an alcoholic, and one of the things you learn is that dramatic changes are par for the course. I would quit drinking for stretches to prove I "could". I'd pour out the whiskey (I kept stashed), to prove I didn't "need" it. Eventually though, I'd buy more. In your case, canceling pre-orders and selling stuff off is a grand gesture, but the tendency is to believe that is enough. Once you've done this, things will be "fixed", and you'll gradually slip back in to old habits. So, much like your wife needs to share the bigger picture from her point of view, you'll also need to spend some time looking at your collecting habits, why you do it, and why you are willing to risk the family budget in pursuit of it, even "accidentally".
Finally, no addict can be successful attempting to get clean for someone else. You have to decide it's important for YOU to make the change, whether or not your wife sticks around. Hopefully though, demonstrating this willingness for introspection and taking concrete steps towards change beyond the grand gesture might help her to come alongside you.