Retiree insurance question

Back in 2018, I quit a job and started a new one. I began drawing a pension from the job I quit. I did not sign up for retiree insurance because my husband worked for the same company and he started supplying the coverage/I went on his insurance. (I had held the insurance while I worked for that company and we wanted to stay with them because the coverage was better than my new employer.) Flash forward to now: my husband is retiring and qualifies for Medicare. I am too young. I know that COBRA will give me 18 months of coverage. What I would like to know is if my past employer has any obligation to offer me retiree reinsurance (I pay the premiums but would be covered under them) I would prefer this so that I didn’t have to look for ACA coverage after 18 months. I need coverage for a total of three years. I am also wondering if the company even offered me COBRA when I left. I do not recall them doing so. I’m thinking that they should have even if I signed up under my husband for insurance…I have emailed them to ask but it has been 4 business days and I haven’t heard anything.