I've Made previous posts on here about a casual relationship I've had for 2 months with someone but wanted to get some advice on developments. Basically this started as me wanting something casual and her wanting a relationship, then we flipped To me wanting a relationship with her and she wanting something casual. She then ending the possibility of a relationship and I tried to see how we could keep it casual and draw up the boundaries for that. And i thought I had it figured out were we could sleep with each other, text in the week but she wouldn't tell me about the other people she's seeing and I wouldn't be involved on that. I'd obviously be more happy to pursue this if I was also seeing other people but I'm not and don't really have any avenues for that right now which is what makes this harder.

So cut to where this has changed. I recently went to a party at hers and it ended up going on till 6am and I was staying over at hers but mainly as I had no way of getting because because of where I live. It turns out she had invited a series if people to the party shed had sexual relations with and a few of them had left leaving me and this other guy I'd never meet. She basically wanted to orchestrate a threesome with us and neither of us were bi and didn't want that but from a point of with Jealously neither of us wanted to back down for the other person to sleep with her. This threesome then ended up happening and was extremely awkward and strange and left me feeling very vulnerable, manipulated and used. Before I felt like she genuinely cared about me and liked me but did t want a relationship right now and now I just feel like I'm a number on a list to her and just another way of getting off. I get that we live in a very sexually liberated society right now and it's very much the thing to explore your sexuality in your 20s but this has left me feeling really used and unwanted and unloved and I'm just in a bit of a hole about the whole thing.

So what I'm basically asking is what to do next. As one option is to call her, explain why I think that whole situation was unkind and set strict boundaries for any casual dating here on but also like takes 2 weeks of no contact to deal with it. Another option is block her on everything and never speak again. And another is still call but have more of an argument where I get all this honestly out and anger towards her and just say I do t think we can have any relations going forward as clearly I'm too emotionally invested for this to be causal sex. And I don't know what to do as I really enjoy seeing her and do t want to lose that to go back to having nothing. Could really use some advice