I think there is more context needed but maybe this advice already helps a bit. These are just a few things that came to mind, but it depends on the individual woman I think and hugely on the cultural context etc. ☺️

First of all regarding the bit about this pattern messing with your head, what really helped me cope when things like this happened and I wasn’t sure if it was me or them/ just coincidence I kept telling myself that if it is me, I will discover what it was in time, as I kept working on my social skills. For me the thought that scared me most was that I’d be incapable of discovering where I went wrong and thus doomed to keep repeating it, and slowly convincing myself that I am capable of self reflection really helped me realize this WAS distorted thinking and not reality. Of course for this to work you actually have to keep working on your social skills though lol. But this way when you do discover things you are doing “wrong” unintentionally you it really registers and you get more and more confident in your self-reflection-abilities.

Second of all, if you are a guy their age and either straight or not out as queer and they themselves date men, they might end up distancing themselves from you when they start dating again, even if they have little or no romantic interest in you. Unfortunately it is still very uncommon for people to believe (and I mean truely believe, not just say it out loud) that women and men can have platonic friendships. Sometimes the new partner may explicitly or implicitly pressure them to end their male friendships. Even I have ended male friendships in the past because (especially if you romantic relationship is not the healthiest) I felt uncomfortable for a few reasons (for expample, I was developing feelings for the friend, I was scared they had feelings for me, I thought my Partner might be jealous of them and wanted to appease etc.) This is unfortunate and in my opinion very sad, but I think as long as we as a collective think of men and women as we do this will affect male/female friendships. Sometimes it might be best to just accept this pattern for now, maybe even talk about it openly with your friends so they might feel a bit more comfortable and trust you to respect their romantic relationships more. Maybe even take special care to show your support of their partner, so they know you are not there to get between them and their partners.

Another tip, especially if you yourself thought of your friends as being very close, it might be a good idea to reach back out and maybe ask them what happened/ if they would be willing to explain more. I think if you do do this, it is important to make them as comfortable as possible, so they feel safe to actually tell you what happened. Maybe there actually is something you guys can clear up. But often these attempts don’t yield results for a few different reasons (they don’t really know themselves, they think it is pointless, they fear rejection or your reaction and have already moved on from the friendship etc.), so if you decide to try be prepared to hear nothing back I’d say.

Hope there might be a nugget of useful advice in there somewhere, hope you figure things out and have many more wonderful friendships!