What if an emergency happens to the sole caregiver?

Regarding the wearable alarm with the motion sensor that Beatty mentions - I rented one of these for a woman I took care of. It worked as advertised. She had an unwitnessed fall with likely LOC. The alarm necklace detected the fall,, called authorities and they came and took her to the hospital. Just be careful on pricing because I recall that not all of these alarms HAD the falls detection feature and I recall there was an upcharge to get that - some were just the button that would need to be pressed (but would not do any good if the person wearing it were unconscious). If you're comparing prices, just make sure you're comparing apples to apples because the ones without falls detection were indeed cheaper.

Yes it's a tricky one. You could get a wearable alarm (necklace or watch) & hopefully press the button, some fancier ones will have motion detectors. If reception is good, carrying a mobile phone would instantly raise your safety level.

I would assess both the risk & consequences.

You are young & pretty healthy, right? So very LOW risk of faint, heart attack, collapse. If you tripped & broke a bone, most people could still crawl to the phone, unless they injured their back or hit their head. Chance of that LOW. Outcome of DH cannot call EMS or bring you the phone.. unknown..could be LOW with a sprain to HIGH if a head wound.

It's a good question. It may lead you to start asking others.

Q. What are your medium to longer term care plans for your DH?

Q. How will you obtain a sitter or home help if/when you need to?

Eg when DH cannot be left alone or brought along for shopping. Or help him wash if he refuses?

Q would you like to be closer to family/friends/activities?

Q Who would care for DH if you had a broken leg?

Generally they are BOTH taken to the hospital by ambulance. You need to have a posted (on refrigerator) notice in your home that your spouse or SO cannot be left alone as is not competent. This should be in your wallet when you are out alone as well.
As a nurse we often had spouses brought in under these circumstances; The spouse was hospitalized until social services found placement during the caregivers acute hospitalization. We even had animals at home brought in to the shelter during hospitalization of family members. Just be certain the info is easily available. EMS workers are taught to check refrigerator door for POLST regarding DNR or DO resuscitate orders extant for a person.