newist... Your husband has got an aneurysm, and you must have been told that IF it bursts, he would have a VERY short time to live? If so, then it could happen when you're asleep/having a shower/making a drink, anything. Sorry, but it is impossible for you to be with him all the time. Have you heard of Crossroads? They are a nationwide company, who have carers to be with someone, in order for the spouse/relative to have a short break of a few hours. I worked for them some years ago, and I went to people like you and your husband every day. You have to look after yourself and be kind to yourself. You need to get your rest, or you will be unwell.
Best of luck x