Sucking dick

Help!!! I used to make my ex cum sooo fast when I would suck his dick. He would cum every single time. I didn’t mind sucking his dick because I didn’t have to do it for a long time. I actually liked to because it made me feel good about skills! But I’ve been with my new boyfriend for a year now and he takes forever to cum when I suck his dick to a point where I have to give up. I’ve only made him cum once :( I’ve tried using my same techniques from my ex and new techniques and I still can’t manage to make him cum. I feel like I’ve tried everything, and I feel so insecure when I can’t make him cum. Please help I’m desperate!!