my boyfriend can't make me cum

Hello! I'm l7 and I've never been able to orgasm with someone else. My current boyfriend is the only sexual partner I've had, and I'm his. We're both fairly new to sex but are really loving it lol. He's amazing at fingering, nipple stuff and he always wants to make me feel good, but I've never came. He goes down on me a lot but never for more than like 10 minutes. It feels good when he's doing it but he always try's to switch it up during the process. Like he'll go really light then hard then light then somewhere else that isn't my clit lol. But I know he's trying. I kind of just want constant hard stimulation on my clit. Anyways I guess I'm wondering. Anyone not able to cum w their boo? He's really understanding and I can be honest with him. I'm pretty adventurous and eager to try things and he's usually very open about whatever it is I wanna do. How can I get myself to cum? What do I tell him? Have you guys had this problem?