Help!

Okay so my first sexual partner I thought was so great. I was 18 at the time and once we had sex in the beginning it was everything because it was all new but I NEVER was able to cum. As time went on we had more horrible sex than good. We separated and I started dating another guy that was amazing in bed. He knew my body inside and out. I would always have multiple orgasms from both penetration and oral sex. It was like a drug to me. I needed it all the time! Once me and him separated I reconnect with my first and we tried again. Compared to my second he is EXTREMELY small. I could barely feel anything at all. When soft it is the same length of his balls and While hard it looks to be 3-4 inches and the other guy is about 3-4 soft and 6-7 hard. How can I make the sex better with my first? I was for the lack of a better phrase sexual spoiled by my second. I want to be satisfied but I’ve never told him how most of the time it was bad for me so I’m not sure how to tell him it’s even worse now. The oral sex doesn’t even feel good even with all the advice I’ve given on how to do it he still can’t get it right. How can I improve his “sex game”?