My two cents is that no, it's not 'fucked up'.
If I may tell a story:
2-3 years ago, a girlfriend and I went to a motel rather spontaneously. It was early afternoon, but the manager had no problem letting us check in early. Of course, we were going to take care o' business ASAP, but I had to bring in a few things from the car, and while I was doing that, my gf had taken her clothes off and had put just a t-shirt only on.
I started to flip the TV on for some background noise, but it wasn't working. I called the manager and he came to the room with some different remotes to try, and when none of them powered up the TV, he said he would just put us in another room a couple of doors down. He gave me the key to that room, and as I went to go unlock it, the 'maintenance man' and his helper showed up; he said he knew what was wrong and would have it fixed in just a few minutes.
So there is my gf, in a motel room with 2 strange guys, barely dressed, nipples poking, and the t-shirt had her tits outlined perfectly. Long story short, they both fucked her while I was in the other room, one keeping a watch out for the other. She came to get me after the 2nd guy had finished, said we were staying in original room, and we headed back.
She not only didn't tell me, but wanted to get in the shower immediately before we started foreplay. Their cum was running out of her pussy as I washed it. I remarked she seemed "extra creamy", and she agreed, telling me it was just the moments we were sharing.
However, after the shower, she presented her pussy to me for me to eat, and it didn't take long to put 1+1 together. Swollen lips and stretched pussy, still creamy, didn't happen by playing tiddlywinks. At that point, she told me what all had happened to her.
The point is I wasn't offended or angry. I would've liked to have known or found out sooner than I did, but just for purely personal reasons.
A new boyfriend or a stranger may be put off if they didn't know, but it's not the end of the world. Besides, they should be able to tell by the condition of your pussy, especially if your last fuck was within the past few hours.