Perhaps a jealous RL partner? I’ve heard of that kind of bullshittery.
Frankly, any person that asks me to dump a long term friend for sex is probably not worth the trouble or the sex.
That DID cross my mind. Last I knew, there was no RL partner.
But, it is entirely possible they got one between the last 'sit down and catch up' because the two of us have a very long history together, have been very close (did briefly date, disastrously, when we were 21), so I could see that sort of scenario. And while I am with you (I want my SO to have friendships: my ex-husband was so clingy I would frequently shove him out the door to go hang with his friends), I know not everyone feels that way.