I used to be really scared of that. I still hate it. I used to not enjoy getting close with anyone because of the fear of loss! I've had a lot of tragic loss in my childhood, so that may be why.
Lately I realize I am strong, I am my own person. It would be horrible to lose the love of my life, but I'd still have my inner strength, animals, friends, family, strangers, acquaintances, travel, interests, passions, hobbies, random first-world pleasures.
I'm not great at being single for long periods of time so I'd have to move on. I really flourish with companionship and touch and sex and nurturing. Any partner who I'd love so much to be devastated by their loss would want me to move on and be happy, absolutely.