First you find out the facts using a subpoena to his employer. Assuming for the moment that he did lose the job, he must prove it was not his fault,and then show efforts to find replacement employment. This can get complex and you should think about an attorney helping you.
Enforcement of a pendente lite (temporary) support and maintenance order is best done by income execution (IEX), which can be prepared in an hour or less. However, an IEX is not available if your husband is off the books or self employed. In such cases, a contempt motion is needed, which could take 4 or 5 hours of billable time, I expect. You can also seek atty fees as part of the motion, which should help.
It's best not to guess, but if there is no response after repeated calls to your adversary, it's fair to assume that your spouse's intention is to litigate -- at least for now. Don't despair, though, since litigation is often used as a tactic to leverage settlement, and is not intended to lead all the way to a trial. So, it's quite possible that you will not need the whole process of discovery. Your attorney should advise you on ways you can leverage the process to neutralize any...
Generally speaking separate property is lost if spent, since courts "declare" separate property but have no power to distribute or recoup it. That said, you may be able to recover monies spent on house repairs to the extent the value of the home was enhanced. There may also be recovery of separate funds invested into a joint account under certain circumstances.
On these facts where you made no contributions to the IRA during the marriage, the appreciation is considered "passive" and is NOT shared with your spouse under NY law. The entire account remains your separate property.
Recordings are excellent evidence. The recording you mention is particularly valuable because it will preempt any effort to claim self defense, which usually plagues men's efforts to get an order of protection. An OP is your first step brought alongside a divorce or custody proceeding, but you must act quickly.
If you are asking if you can receive a share of your wife's retirement savings while not parting with any portion of your own, its not likely, unless your retirement accounts were accumulated prior to marriage. But don' t rule out spousal maintenance just yet. Speak with experienced counsel to learn what rights you have and how a good result can be negotiated.
If your question of whether to divorce concerns only finances, the answer is usually no, since your husband's obligation to support you during marriage is indefinite. That said, your individual situation may dictate a different answer. Of course, social and emotional reasons may weigh heavily in the balance too. Seek advice from an experienced matrimonial attorney for help deciding how to proceed.