I've been through this a little myself. I generally tend to default to my partner or BF in terms of my appearance. After all, he's the one I want to please most, and who has to look at me all the time. Whereas I try to avoid mirrors like a vampire.
My first BF had a short mustache, that was like a stiff bristle brush to my skin when we kissed. I knew he'd had it forever, so I simply grew my own mustache as a protective barrier. That solution worked well, no more prickly kisses.
I had another BF with a short beard, and his face was rough on the skin of my groin when he was down there working on me. Nothing more I could grow of my own in that situation, all I could say was to be careful. Maybe the OP's BF finds the beard uncomfortable when they're being intimate. Have they been together long? Perhaps being more careful in bed would help.
I had a beard when I started dating my late partner. I sensed he wasn't too keen about it, and with the hot humidity in his city of Houston I wasn't so much anymore, either.
So I told him my intention to shave it all, and he said fine. When I came out of the bathroom he was shocked & overjoyed. I hadn't realized he liked them a little young (I was already 3 years his junior), he just raved how I looked 10 to 15 years younger, and called himself a chicken hawk. It was just a few weeks later he formally proposed to me, and we became partners until his tragic early death.
I asked my current partner if I could try a beard again for a while, I was curious how white it had gotten over the last years. (Answer: VERY) As it was coming in he began to dislike it, but I asked him to be patient and let me bring it to the shape & length I thought would work, then reconsider at that time.
Our friends began to tell me how much they admired my new look (even a few strangers, and my barber also approves), and he began to be won over. Today he says he really likes it, so I've kept it for several months now.
But I never keep a beard or mustache for very long, and when it comes off I'm sure I'll get compliments the other way, if only because of the novelty of the change. And it's only hair, I've always got more (at least on my face). At this length I can grow it back in 2-3 weeks.