No. But they mentioned her indirectly a couple of times and got in a few small digs.And do they even explain Mikaela's absence in the movie(not that I really care), or is it just as simple as she dumped him for Wheelie, oh that would be funny?
In the novel, she left Sam right after ROTF. She couldn't take it anymore. Yes, right after they pledged their love for each other and survived their second giant robot apocalypse.
It would have been better if she died as a Decepticon reprisal between films.
Mikaela had bigger balls than Sam and wouldn't simply leave because the robots got to her.