Girls like attention. Actually guys do too to a lesser extent.

Provided you did not creep her out, get butt hurt or look pained and needy when she rejected you, she has no problem having you as an orbiter. Not an inner orbiter who might get to bang in the absence of Chad or a high value beta but you are welcome to an introductory level membership of her outer orbit where you can bask in her glory and add to it with your devotion.

Spin it round the other way. A nice girl that you don't want to get involved with just made advances to you but you said no -maybe because she is ugly, maybe autistic, Maybe too needy. maybe she is dating your friend. Anyway provided it didn't go badly, you will feel a bit sorry for her, you will want her to know you didn't dislike her personally and you won't actually mind the idea that she wants your dick, so long as she isn't getting stalkery why would you not acknowledge her? Why would you not be friendly? If you were a bit selfish you might even just give her the odd breadcrumb of interest, just to keep seeing that look in her eye. Even though you don't want her, it still turns you on to feel wanted right? Now multiply that pleasure in being desired by 10 and you have a woman.

Unless the ex is a very understanding woman and you not at all jealous (the "not exactly slim" comment suggests not) I don't think there is anything you can really do. Its more about what you don't do and how you react if it gets to your girlfriend.

If you squirm, the ex will be more inclined to stamp on you. Take the outward approach of feet together and accept the landing. Don't act ashamed or afraid whatever you do.

Don't beg, don't blackmail or threaten. Just hope it will pass. Try to do nothing. If the ex presses you on it say; well you can't help still having a thing for her. Sorry but feelings don't just vanish when they were genuine. Its a compliment and women like compliments and like having reserve guys. That security might buy her off but you never write anything so crazy and you never say it if she might be recording you. In fact you put nothing in writing to her about what you have been doing. Call her if you need to (and only if you really need to) and get the job done in one. She is unlikely to record the first call, even if later she wants evidence.

You need good responses if this comes out. Deny where there is any doubt. If cornered by facts and evidence make a full confession (not a partial one where more evidence could show you up for being a liar). Own up straight that you did wrong. You won't do it again. You are sorry. Then carry on like normal. Do not crawl.

This could well blow over, if you can avoid a jealous woman smelling blood. It just might be saved if the ex doesn't want you to just vanish on her and likes it that you still have a thing for her. You stop all suggestive contact but in the time taken for her to realise that she isn't getting anywhere the whole thing goes cold.

Leading the ex on to think she could have a current relationship with you would be be very dangerous. Then you could get into far hotter water. Railing her to keep her quiet would be a ticket straight to chaos. If she does press that she wants you back, explain that you still want her, of course you do but you also let yourself get carried away as you are in a current relationship. How could the ex respect you if she knew you were unfaithful to the present one? No you have to play this hand out. Sorry for getting to into her and getting carried away. It would have been different if you were both single.

In these things the woman you live with will almost always win if she wants to win. She has the advantage of possessing the territory. If she relaxes and sees this, your girlfriend may settle down about it. You come home to her. You just messed up but you had already stopped before she found out, not after.

I‘m exceptionally goodlooking so maybe that changes the dynamic.

????This is a question use a question mark.

I am quite inhibited when it comes to approaching women

Fix that problem

So here's the problem with IOIs. They are absolute bullshit. Some girls are just friendly. Some may smile and that doesn't mean that they want to sleep with you. It's called being social.

Let me break this down into more simple terms. If a girl says yes to going out with you, that's an indicator of interest. If she initiates a flirty sexual conversation. That's an indicator of interest. If she becomes your girlfriend, that's an indicator of interest. You can sit in imaginary land and and Miss can true vague signals as interest. The truth is you're just wasting your time and your energy on someone that could not give a shit.

This is a phenomenon that irked me ever since my first approach when I was 13. I approached this older girl at school after weeks of her giving IOIs (stares, smiling), I just walked up to her scared as fuck and awkwardly said hi and asked how are you. Got rejected in a harsh and embarrassing way, but just a few weeks later when I saw her again and she was giving me IOIs again, smiling at me.

Same thing happened again several times after that, in fact I struggle to remember a single time where something like this did not happen (I’m talking about girls I would see on a regular basis).

I‘m exceptionally goodlooking so maybe that changes the dynamic.

Why does this happen? What should I do about it?

Obviously if it was an unfriendly rejection I will just ignore, but say she rejected me in a more ambiguous way (has a boyfriend, or I already fucked her friend, or another dumb reason). Is it fair to treat this as an invitation to talk to her again? I am quite inhibited when it comes to approaching women, and my worry here is that it’s nothing more than a good way to try and get rejected a second time, boosting her ego and making me look desperate

Attempt to answer own Question: I would try to have a low stakes conversation first, then gauge interest based on that.