Help!

I have this little problem I need some help figuring out.....

I'm 17 years old and I'm currently in a relationship of 2 years with a guy we will call J. J and I have been having problems with our relationship for the past year. He cheated on me, I've cheated on him. And now ive found this new guy we will call S. S is 10 years older than me. He also has 2 kids, the oldest being 9 years old. I really really like S and my feelings for J have been diminishing for about 5 months now. But my problem is is that I dont want to break up with J if the feelings and relationship with S aren't real. I feel that because of the age difference, S just wants sex. He tells me he likes me and everything but Idk. S treats me way better then J ever has. What should I do? I'm majorly afford of getting hurt. Ive been hurt so much already in the 17 years of my life. I'm scared to get hurt and I don't want to hurt anyone else. And I know if I break up with J that it would kill him inside because I know he loves me but he doesn't treat me right. Idk if my feelings for S are just because of the fact that the relationship with J isn't good anymore and I just want out and he'd be my way out. Idk can someone just help me through this. Share their experiences or give me some good advice? Would me amazing!!