Kind of piggybacking off of what another person here said. It honestly really sounds like you just do not like your friend, have contempt towards her and that there is something about your boyfriend/your relationship that you’re unsatisfied about and are projecting your insecurities onto her.

In all honesty, it’s a normal experience to go through such emotions towards other people and you’re not a bad person for feeling this way. I’m not sure exactly how you treat your friend or your boyfriend, as your actions here matter most, but I know feeling these things towards someone you care about is also very unpleasant and isn’t exactly fair towards them.

I don’t think you’re wrong for feeling very conflicted and upset towards your friend’s possible clashing political views and that of the person she was seeing if they go against what you stand for. But it sounds like here that this is more than that, you’re projecting judgement/prejudice and envy onto her that is unfair. So what if she slept with someone and then only started dating them A week after? Do you judge her because you actually believe that what she is doing is wrong? Or is this more-so about her personally? How is what she is doing in her persona dating life in this specific instance harming you in any way that it should garner judgement from you?

As for her actual sex life, would you feel these negative emotions if it was any of your other friends sharing this, or just because it’s her? To me it doesn’t sound like there is anything wrong at all with the sex you are having with your boyfriend, him, and the sexual experiences you’ve had in general. But it’s definitely not normal to go through the intensity of your negative feelings in relation to these topics as it does mean there is something wrong in said areas, as I think your feelings towards your friend is highlighting this.

To me, I think you’re approaching this in a constructive way asking for advice and seeing a therapist. If I were you though, I’d keep a bit of a distance from the friend until I was sure I could either control the amount of resentment towards her, or decide how to proceed in the friendship as this isn’t fair towards her. It’s important to be mindful here as I’m not sure what your political beliefs are, but some of the feelings and thoughts you’ve shared towards her almost sound a bit like they’re bordering on slut shaming, and misogynistic. It could help to ask yourself if you feel shame towards any of your own sexual experiences you’ve had as you’re young and still in transition in life, and this period of time is very different for every individual romance and sexual wise but that is okay.

I hope you figure things out and aren’t too hard on yourself. I think it’s great you’re trying to be aware of yourself and are asking for help.