The good news is that if you can orgasm when you are having sex by yourself using a vibrator you can almost certainly figure out a way to have orgasms when you have sex with your partner. You should know that the predicament you're in isn't that rare, and it isn't really surprising. On the one hand, vibrators are an incredibly efficient way to have an orgasm. They provide the kind strong and consistent stimulation that most people need to have an orgasm. They can also be a lot of fun. And on the other hand, as a result of little to no sex education and a whole lot of cultural shame about sex, many people don't learn how to engage in sex play that provides enough stimulation to produce an orgasm. Particularly if you are expecting to orgasm from intercourse alone.
There are plenty of things that could be getting in the way of you orgasming with your partner. I'd be curious to know if you have ever had orgasms with a partner. If you have, do you have a sense of what is different with this partner? Sometimes we assume that we don't orgasm because there's something negative lurking beneath the surface. But for some people being in a committed, loving relationship itself can feel strange or threatening, and letting go enough to be able to orgasm with a partner can actually be more difficult when it is with someone you love than when it's with a virtual stranger.
Not Enough, or Not the Right Stimulation for You
The easiest problem to fix is if you aren't orgasming because you aren't getting enough stimulation during sex with your partner. Vibrators provide more stimulation than any human body part can. So one question is, how much stimulation do you need? You may just need a lot of stimulation because that's the way your body works. If you know this about yourself, can you talk with your partner about what you need to get over the top? It might mean reviewing a few techniques (learning how to use their hands, mouth, or other body parts to provide stimulation). You may also have to tell your partner where you like to be stimulated. If you have a clitoris, it's likely that clitoral stimulation is important. But maybe not. Maybe there's another body part that is extra sensitive. No matter how much love and comfort and chemistry there is in a relationship, none of us can magically know where and how to touch a partner. It can feel awkward at first, but talking about it is key.
There are also medications that can make orgasm more difficult. It's possible that with a vibrator you won't notice, but when you are without one the difficulty with orgasm is more obvious. If you are currently taking any medications this is something you may want to talk to your doctor about.
But the easiest and first suggestion I have is to use the vibrator with your partner. If it feels comfortable you could start by simply masturbating with your vibrator while he is in the room. If you can orgasm with him in the room, you are one step closer. Next you could use the vibrator during sex play with your partner (but you keep hold of it). If that works you can try to let him hold the vibrator. Give him some instruction first. If he has never used one before suggest that he use it on his own, on himself, before you try it together. The idea that "real sex" shouldn't include a vibrator is nonsense. If your goal is to have orgasms with your partner and without a vibrator you can probably get there, but it may take time and both of you need to be open to experimenting.
Issues in the Relationship
I need to also say that sometimes when one person can't orgasm with a partner it's because of other stuff going on in the relationship. If you know you are happy in the relationship and with your partner don't take this to mean there must be something hidden that you are unaware of. But it's worth taking a little time on your own and thinking through the various aspects of your relationship and checking in on how you are feeling about them. It might be tied to money or work or where you live, or family. It might be something that happened a long time ago that neither of you felt like you could talk about again. It might not be this at all. But since I'm offering a list, it's a possibility that should be on there.
Negative, Coercive Experiences
Having an orgasm requires that we let go of a lot. We need to let our guard down and relax and focus on ourselves in a way that can leave us feeling very vulnerable. Sometimes we're able to do this on our own but not when someone else is in the room. It might be tied to an experience of coercion (if you've been forced to have sex or felt pressure to have sex) in the past. It might be related to an experience that you wouldn't think as forced or violent but was still very negative. If you have been able to orgasm with partners in the past, think about whether something has happened between then and now that may be making you less able to relax with this partner. If you have never been able to have orgasms with a partner, you may want to try and pay attention to the difference in your thoughts, feelings, and experience of your body when you are alone and when you are with a partner. If you find yourself generally more tense, more self-conscious, more anxious when you are with your partner know that all those things can get in the way of having an orgasm.
If this is the case, no amount of technique will change things. If you have good communication it may feel okay to talk with your partner about this. If you aren't sure, it might be something for you to talk with a counselor or trusted friend about, and then decide how you can bring your partner into that conversation.
Relaxation Is Required
It is also possible that there is no big reason for this situation. It may be that you are just having a hard time relaxing enough during sex with your partner to have an orgasm. Our sexual response is so suggestible and prone to habituation that it could have been that the first few times you didn't have an orgasm, and now every time you have sex you are thinking about it, worrying about is, and that is messing you up. Sexual performance anxiety may be "in your head" but it's powerful, and usually doesn't just go away on its own.
If you think this may be the issue there are many things you can try. It may sound funny, but start with breathing. Again talking with your partner is going to be important if you are feeling any anxiety or nervousness. Keeping that stuff in makes it just that much harder to put aside. It may or may not help to talk with a sex therapist and that might be something you want to do alone or with your partner.
The Bottom Line:
If you can orgasm on your own you can learn to orgasm with a partner. It might not happen quickly or easily, and I know that can feel frustrating when you are in a loving relationship. It can even feel like a betrayal. But what may be going on is nothing more, or less, than a disconnect between your body, your thoughts, and your feelings. Bringing two bodies together always makes things more complicated and you should know that contrary to almost everything you see in the media, there are plenty of people who struggle to have orgasms with a partner. You should also know that if it feels worth it, and you can work together, change is not only possible, it's likely.