When to seek medical intervention for orgasms?

I'm nearly 24(will be in a month) Ive only been sexually active for the past six years, but I haven't ever found much pleasure in sex. Penetration only feels good for about a minute and then fades away to nothing, I have never orgasmed from penetration. Clitoral stimulation gives me a little more pleasure that will build and then disappear as well, but it's never pleasurable enough to cause even a little moan. It's definitely not anywhere near the explosive, moan inducing, satisfying, climax's people talk about. It's honestly not even worth the effort. Ive tried vibrators and different kinds of toys. None of them make it any better. It might happen quicker but the intensity is always so severely lacking that it's still not worth the effort honestly. No partner Ive ever had has been able to make it any different. Ive been with my fiance for five years now and we communicate well about these problems and we've tried everything we can think of with no luck. I know it's not his fault, I'm good friends with his ex and they had a great sex life. But I'm never satisfied with sex. I'm always left feeling completely underwhelmed, but we do it anyways because while I don't get much out of it, I can at least feel happy that he's satisfied. We've got two children now and I had hoped it would change after having them but it hasn't at all. I'm starting to think there's something wrong with me. Ive tried every method I could find on the internet and nothing seems to help. When do you seek help from a doctor about something like this? How do you even bring that up? What do you tell the receptionist you're making an appointment for? Will it even help?