So I think I royally screwed up a situation with one of my current interests ("Girl A"). We had sex on our first date 2 months ago and since then have been seeing each other about twice a week, usually after bars close I go to hers or she comes to mine. When I met her, I was having sex with a few other women, but I am not right now. I have been on quite a few dates recently with other women, and have 2 other women that I really hit it off with and will see again.

The other day Girl A started the "relationship talk". I told her that I wasn't looking for a girlfriend, she said cool, she's not looking for a boyfriend. Then she asked me if I was having sex with other people. I said I wasn't currently (true), but that I was when we met, and didn't want to be exclusive. At first she had a huge problem with this, and said she wanted to be exclusive. I told her that didn't work for me. We talked about it for a long time, it was a good talk. I thought she'd probably "break up" with me, but she didn't. Instead, she said she thought she was OK with it, but that I need to tell her if I've had sex with someone else. VERY stupidly, I agreed to this, after trying to convince her it was a bad idea.

It's obviously a semi-manipulative ploy/test to test me and/or get me to commit to exclusivity.

The situation I'm in now is that I have 2 other girls lined up this weekend and will definitely be having sex with at least one of them, maybe both.

My plan is to see this girl tonight or tomorrow, and tell her that I'm going to probably have sex soon, and that I'm not going to tell her if/when I do because I think it's a bad plan.

Any ideas/feedback on this plan? Ideas on a better way to approach it? I definitely want to keep seeing Girl A, she's really cool and absolutely amazing in bed and we really like each other. I think if I tell her after the fact, she will probably break it off or at least get all weird about it. And simply not telling her about having sex with other people is not an option for me, that's not how I roll.

EDIT: posted an update.