I have been in this situation. Actually to the point where I, like you, am pretty sure it's more my issue than the other way around. Being relaxed is really the way to go. Along with successful communication, sometimes a sense of humor, feeling comfortable enough with the person to stop as soon as it gets the slightest bit uncomfortable OR ceases being pleasurable- that is your body giving you a warning. You need to heed that, because the more times you end up with pain after sex, the stronger the association becomes between the two, the more you expect that it will be painful, the more difficult it will be to relax, the more likely that it will be at least uncomfortable... see where I'm going?

It can be a difficult cycle to break, but really not at all impossible. You are likely going to have to talk about specifics and use specific terminology. And that's ok. It's how you build trust and strengthen communication.

Also- lubrication is a definite yes.

If you use water-based lubrication, you may have to reapply in the middle of intercourse, and that will be a more likely situation the first few times you use it because you may still have the association with discomfort. This could be awkward, but doesn't have to be.

If you use silicon based lubricant, they really don't dissipate but you need soap to clean them up.

I would recommend not using any of the crazy hot/cold/tingly/whatever lubricants. They will send your body weird signals and you won't be able to tell if you are getting any warning signs.

Um... I feel like I'm preaching.
I don't know if you do or don't use any of this stuff, just figured it might be helpful for whoever reads it.