1. As hard as it might seem, you will need to try to lessen your panic, as this, alone, can weaken your immune system. Try to redirect your thoughts to something positive, when you begin to worry or think too much about catching his illness.
2. Take Olive Leaf Extract, and, if available, take a combination of Olive Leaf and Neem. The olive leaf extract on it's own, is a super immune booster, so, it will work sufficiently, but the addition of Neem will enhance it's effect, tremendously. I take one 500 mg capsule in the morning. If you begin to feel the onset of a cold or flu, take an aditional capsule in the evening.
4. Take a good probiotic, or eat foods and drink teas, rich in probiotics.
3. Drink, at least, 8, 8 ounce glasses of water per day. Try to drink more, however, drinking too much water (not sure how much is too much, but would look it up), could be detrimental.
4. Stay away from ALL sugar substances, including fruit, fruit juice, and anything else that remotely tastes sweet, because germs, bugs, various microbes, fungi, etc, feed off sugar and anything that turns to sugar in your system, including grains, breads, pastas, etcetera.
5. Eat a lot of leafy green vegetables and colorful vegetables. Don't eat to many, if any carrots as they are higher in sugar. A green apple is healthier, in terms of sugar content, and, if you must have something sweet. But, if you dont need or crave sugar, best to stay away from all of it, if particularly suseptable to contracting illness. Sorry, I went off track. Eat foods rich in vitamins and minerals.
6. WASH YOUR HANDS more frequently than you do, normally, when in contact with your partner, or, anyone else, who is fighting an illness. You may also benefit from wearing a mask or scarf around your mouth and nose, while in his presence.
Just some things that I do, as preventatives/precautions and I will write, again, if anything else comes to mind.
Best wishes...