I also found out, from our talk and confirmed in her emails, that they are "getting to know each other better". This, to me, seems dangerous, like it's leading her down the path to falling in love... Not sure how to stop it, though. Another picture sent to him and not to me, although our talk did reveal the existence to me of more pictures, so I'll have to find a non-pushy way to ask about those.
The bottom line is that it's obvious that I'm not enough for her, sexually. I'm sure she wants me to be included, at some level, and I believe her that she can't imagine her life without me in it... but she spends her day thinking about sex with him, creating inspiration to send him pictures (but not creating inspiration to send me anything, even though the inspiration should have been the same, as today it was about my favorite football team...), and even thinks about him when she's with me. During our fingering session last night (two fingers on her clit, one up her ass), she asked what she had to do to get a sandwich - meaning a threesome... again, obviously I'm not enough for her. That hurts a bit.
He distracts her from me, I'm not adequate for her needs, and she seems to be more interested in building her relationship with him than with preserving her relationship with me. I can't make an issue out of this, not so soon after healing the previous rift... but it's going to have to be raised one of these days.
We'll have to see how tonight goes, and this holiday weekend... hopefully she'll be able to focus on me, and not spend the entire time texting him.