Scared of losing my fur baby Koda

I lost my cat Simba last Christmas after he was hit by car. My bf found him and he was heartbroken as he developed a strong bond with him. He was 14 and had 2 brothers one who already hit by car a few years back (Kenai) and one who is still with us. I lost his mom Twinkle last year with heart failure and my eldest cat from old age (Tiggs - he was 22)

I so scared of losing Koda. I love all my pets equally and each one I grieved and still am at times when I see photos or reminders. He is 15 in July and we had him since he was born. I want to cherish every moment as I know sadly he won’t always be here but I’m too scared to let him out when he wants to but I do let him out but I get so scared. How can I let this thought out of my head and cherish all memories I have got and memories yet to come.

This is Koda - he loves snuggling in any warm place. (He’s my little firebug) . He always sits on my lap and goes to sleep unless he’s hungry. He loves my bf as he sits on him when he’s home otherwise it’s me lol. He’s 15 in July.