We don't know you to be able to say exactly why you feel guilty, that something you have to figure out through self-reflection. However, one reason might be oneitis. You might be, for some reason, putting the first girl on a pedestal. Nothing bad about that, we all do that. But it could be good to think about why. You mention yourself that you can't do longterm, but maybe if it was possible you'd like LTR? If that's the case, maybe you just have started to have some feelings for this girl (although it's a bit soon after just two dates). Also she put out rather quick for a girl you should consider for LTR.

Another reason you could consider is that maybe you're having some dating fatigue. You mention that you've been in somewhat of a flow state. Sometimes it can get a bit overwhelming too. Like having too much of the cake and then wanting to puke.

Idk dude, what do you think yourself.

Personally I remember when I had flow state and had multiple dates every week that it came to a point where it was so easy it wasn't even fun anymore. I remember kissing this one girl in the bar and feeling... nothing. Seriously, nothing. It was a completely empty experience. I ended the date early. Didn't date for a while and then when the urge started coming back I started dating again.

Regarding oneitis, I've had that too. I've been on dates with some girls that I consider "better" than other girls (and sometimes they actually are), and I get self-conscious about updating my dating app profile because what if she notices? Or I think, what if she sees me on a date with another girl? Or even, what if I accidentally swipe on one of her friends and she talked about me?

You see what I mean...

Bro. This is you taking care of your biological urge, vs societal pressure. I've been there. You are hardwired to spread your DNA. Society seems that bad. Let me tell you something about society. It run by a bunch of lame idiots. I'm 46 I've had a lot of time to see weird shit and stupidity. I was married. It sucked. I have. Been monogamous. It definitely can suck.

I got to a point where sex would just kinda fall in my lap. It still does really. I got to a point where I had 8 plates and I started forgetting what I did with each one. It wasn't fun when it became too much work, but it can be fun.

What you're feeling is normal. You'll get used to it and stop worrying. If you're not reliant on any one girl for sex, you will not be concerned about the consequences.

tbh I have less casual sex than I used to because it's always a little sad letting plates break. I just remember that these women also reject a lot of men, and that I myself have been rejected countless times . . we can't always get who we want. Also likely these chicks are getting dick somewhere, even if not the same day they date you they have some kind of casual thing going on with someone too. So what are you feeling guilty for . . they are probably doing the same thing and they don't have any claim to your time.

But if it really bothers you then don't do it, that simple

Women like men who fuck. Neither of them is your girlfriend. If she likes you she'll get over it because you're the guy other women want to fuck