How to suggest that ADHD might be worth looking at?

I am new to this forum and looking for advice.   I am at my wits end and think my husband has ADHD. I am trying to find a way to delicately bring up the subject with him. I have a strong feeling it will end up that he completely shuts down or a huge argument. How did your ADHD partner get diagnosed with ADHD as an adult? Did the non-ADHD partner urge him or her to get diagnosed?