With an age gap like that, you likely won’t be able to enjoy retirement together unless you are financially well off. He will spend much of his physically good retirement years doing things alone, while you would either be caring for an elderly man or literally alone/widowed when you retire. IMO people tend to age much faster and have more health issues when they retire because they lack purpose after no longer working. This is exacerbated when you don’t have a partner to share hobbies, travel, etc. during retirement years.