How do I orgasm?

I’ve been having sex over a year now with my SO (he’s my first) and I’ve never orgasmed. It’s not because the sex isn’t great, he works very hard to make sure he gives me attention and I always feel so much pleasure and like something is building up but I can’t actually finish? Could someone give me any tips on this? It’s so frustrating. I feel the stimulation and I get wet but just no orgasm. It’s so frustrating walking away from sex still feeling aroused.