Yeah, I can see the point there (And that's not ripping on the writer. I said to a minimum, not non-existent). But to be fair, he slept with Maria before he started to delete... or before it had taken any real toll on his brain. And you know, maybe they're not so much mad at Tony as they are at their own stupidity for sleeping with Tony despite the two of them knowing better.

Maria: probably thought she was going to be his last one for the road. She slept with him in the moment, taking advantage probably less than Pepper was and the exact thing she said was "no future." They both expected to be dying and not coming back from this... and then he boinked Pepper too? That's just typical Tony Stark. it does make him look like a cad on her end.

Pepper; While she may have been the one who took advantage, it certainly doesn't help her psyche that she thought she was acting on emotions they've both had and buried since the beginning of Iron Man. She finally succumbed to her feelings for him, despite herself and then she finds out that she was just the next in line of people he was sleeping with along the way. From her perspective, I can kind of see her feeling like she was played... even if Tony didn't do it on purpose.