I'll give some advice that helped me and my partner, with the exact same issue. I have no problem orgasming, but my partner struggles. We have found that focusing on the most gender euphoric parts helps her finish, in her case it's gently playing with her boobs while she's topping, which allows her to focus on that rather than the other physical sensations. Penetration, while not a negative experience for her, in fact she very much enjoys topping, still isn't the most important part of sex for her. This advice might not be relevant to you if topping is very euphoric for you, but focus on the parts of sex that are most euphoric. Fulfilling each other's kinks also helps us!