(Sorry this is super long) I don't even want to type this out (still in denial) but I need some advice. Me (47F) and my bf (24M) have been together for over a year. This whole relationship has been like a dream. I finally found a partner who was loving and patient with me. Always considerate of my feelings. Caring, supportive, everything I've ever wished for. We met at work and there was an instant connection. Despite the age gap, we had much in common. Similar interests and compatible outlooks on life. We both have young children, I have twin 12-year old boys and he has a four-year old daughter. My kids love him, he loves my boys; his daughter loves me, and I adore her. We take them on trips, go to museums, amusement parks, etc. My family loves him, I love his family. We're supposed to go with his family to Cancun in two weeks. We set up a joint savings account and were planning to buy our first home together. I truly love this man and have felt truly loved in return for the first time in my life. This past week, I've noticed him being distant. Forgetting to call or text, coming to events hours late. I was getting that feeling in the pit of my stomach that something was wrong. Whenever I made a comment or even just asked, "Is everything ok?" He would apologize profusely and claim there was nothing wrong. I chalked it up to his ADHD and my anxiety but I couldn't shake the feeling he was pulling away. Tonight he admitted he had been thinking about things and he doesnt want to continue a relationship with someone who is going to die 20 or so years before him. He doesnt want to be alone suddenly at 50 or 60 or whenever. This seems to come out of nowhere. We have talked about the age gap before and I was always the one who had reservations, not him. He says there is no one else but I can't believe there isnt some other reason since this seems so sudden. I know I've rambled enough but had anyone else had this issue? Is this really the end? I'm trying not to absolutely break down; I just love him so much and I don't understand.

Tl;dr: Me and bf have had blissful relationship for over a year until tonight where he said he didnt want to be alone later in life so is breaking up with me now.