I don't know who to choose

Hi everyone, any advice you could give me would be extremely appreciated. I need to decide between two men that I care very deeply for. I know it sounds melodramatic but I am completely confused. The first is Jason. He was my high school sweetheart. We dated for 3 years in high school and for a while when I was in college. My family does not like him because in high school we were completely wrong for each other, but that was the strongest love I have ever felt, maybe because it was the first. Him and I have been talking again lately because he is going through something very difficult and needs friends that can get him away from it for a while. His father, his last remaining relative, is about to pass. Jason has had to drop out of college for the time being to take care of him. He seems like he's changed a lot and we now seem like we would be perfect for each other. He wants to give it another try, but I have a boyfriend, Thomas (both names have been changed). I have been with him for over a year and he loves me unconditionally. My feelings for him are not as strong as his are for me, but I do still love his company more than anyone else's. He's like my best friend. We can talk about anything and everything. Also, my family loves him and his family loves me, which is important to me. But I'm afraid that if I choose Thomas I will wake up one day when we're married and have a real life together and I won't be able to do it anymore. With Jason I'm afraid he won't have actually changed and things will fall apart and I will have hurt Thomas for nothing. Which should I choose?