Has he ever had any mental health issues before this?

You were asking an opinion from someone who had a breakdown.....for me my mental illness started with a situation.....but the situation initially was at work as I was trapped in a department where I hated the work after being a technical engineer for 15 years......engineer feeling like a glorified secretary & the director wouldn't allow me to look for other positions in the company that I knew existed......the lost it feeling started around Thanksgiving that year.....& it progressed over the month.....I thought that the Christmas break might give me a break but I couldn't go back at the new year & kept calling in sick.....then we had a massive earthquake in Northridge Calif that January & the freeway broke between where I lived & where I worked.....it was a 6 hour drive just to get to work....I tried it 2 times carpooling with a neighbor that worked where I did.....only I lost it.....sat in my office & couldn't stop crying, shaking, couldn't think or even comprehend much of what was going on around me.....went out on medical leave of absence & that forced me to see a psychiatrist & psychologist because my medical GP said that there was nothing physically wrong with me.

Since I don't know your S/O, it's not possible to really judge the situation. Most breakdowns however from my experience & with others I've observed.....it's taken some time to build up to the actual breakdown.....so what you might have seen before this happened as a possible build up.

I know that my anxiety turned into depression & suicide attempts because my marriage was bad & had been from the beginning...at that time it was about 20 years married.....it took a year for it to grow to that point from the breakdown I had the previous year.

Sadly, I have a husband who is good at lying by omission.....he things if he doesn't say it he's not lying....but he withholds constantly information that was & is important to know (I left him 6 years ago.....but haven't finalized the divorce yet).....he had all kinds of excuses for telling me lies or just not saying anything & being totally irresponsible. I couldn't live with that any longer.....I was trapped in the marriage however until my mother died & I got my inheritance....ironic because she's the one that pushed me to marry him even when I told her there were serious problems with his personality.....I wasn't wise enough at the age of 21 to listen to that little voice inside.

My personal opinion from my own experience is that if this guy isn't communicating with you any better than he has been or is now....you need to dump him & definitely find a guy who is much more sensitive to you, your emotions & your needs......it this guy is having a breakdown over the little stuff that happened between you two.........it's only going to get worse when more stress entered the relationship......JMO based on my own past experiences.

Wishing you peace & discernment to do the correct thing.