Michael did not ever marry Joanne Thomae, nor did he have a relationship with her. In fact, she was caught having sex with one of his staff members while he was on the otherside of America and he was told about it and she was barred from Neverland and he never spoke to her again.
Joanne repeatedly lied to Michael about her background and many other things, he found out about this too and was pretty pissed about it all.
Joanne Thomae then, after being barred from Neverland, proceeded to go on TV and lie about what happened, saying she slept with Michael, when actually it was a member of his staff. After this she went back to France.