The good news is that you already know what you SHOULD be feeling and you’re not getting.
It’s absolutely normal that it feels better with your boyfriend. A sexual partner, with the intimacy and surprise that comes with another person feels amazing and it’s why people like having sex instead of just staying home by themselves… If masturbating was an adequate substitution for sex, there would be a MUCH happier world out there…
BUT! The fact that you struggle to find any pleasure at all is not something that should happen. Masturbating, while certainly not better than (GOOD) sex, is a pleasurable activity that teaches us a lot about ourselves and what we enjoy.
My suggestion is to try doing different things than what your boyfriend does to you. Experiment. Instead of trying to replicate his actions, find your own. It may be penetration, it may be clitoral stimulation, it may be both! But I think you need to try a new path instead of trying to recreate what you do with him. You can’t do what he does to you because he’s not there! That doesn’t mean that there aren’t OTHER ways to make yourself feel good.
Try a vibrator. Go slower when working yourself up. Make sure you’re really horny and wet before touching yourself. Relax. Close your eyes. FEEL what your body responds to and act accordingly.
The biggest and most common mistake I hear from girls when they have trouble with masturbation, is that they’re doing what they think they’re “supposed” to do to masturbate instead of giving their body what it’s asking for. Ie. Fingering. You should NOT jump into that first thing. You need to work yourself up, get your arousal to its peak before even considering it. Some girls don’t even want penetration at all.
Stop thinking about what masturbating is “supposed” to be and what it is you do with your boyfriend. Pay attention to your body and find out what it is you like. You have to listen closely and take your time. Once you figure it out, it’s going to make your sex life 1000x better! 😉