Hello, and thank you for your question. I'm sorry to hear about the issues you faced, but am glad to be able to tell you that yes, you should be able to file for social security benefits from your deceased ex-husband.
There are some hurdles that need to be cleared though:
1. You must be unmarried to collect (you should qualify since your second marriage also ended in divorce).
2. You must be 60 or older to receive full survivor's benefits (this isn't known to me yet).
2a. You can begin receiving benefits at age 50 if you are disabled and your disability started before or within 7 years of your ex-spouse's death.
3. Your ex-spouse was entitled to social security retirement or disability benefits, and
4. The benefits you're entitled to, based on your work history, are less than the benefits your ex-spouse received.
If you meet all four of the criteria above, you should be able to claim your ex-spouse's benefits. You'll need to contact the SSA at 1-***-***-**** to apply for benefits, as they're not available online for survivor's benefits.
Thank you, ***** ***** luck to you in the future; please be sure to rate me as soon as you're able.