Can only orgasm from outside stimulation ?

Sometimes sex can be a little aggravating because I can only have an orgasm from the outside. Sorry if it’s TMI, but I’m feeling like it’s not normal, although I’ve read it can be common. Does anyone else experience this and can give me some insight on this? It’s not a huge problem because we still have a great sex life, but I feel like it would be so much better if we could “finish” together instead of me first, and then him, ya know?