My husband has a myspace and has been talking to another woman behind my back what do i do?

[Hope]

Ok so i was checking my myspace account yesterday and i recieved a message from a girl who wanted to let me know if i knew that my husband had been talking to her..she said he had sent her very interesting messages. I asked her what type of messages and she said that they were just talking and that she found it interesting that he never mentioned he was married she didnt find out till she looked over his profile and and realized he was married with 2daughters!! she said that he also sent her a random message about a booty call..Weve had our issues in the past before we got married and rite after the birth of our 1st daughter i found out he had gone out with another female and his friend and his girlfriend when our daughter was 2weeks old..and now with the arrival of our second daughter who is 2weeks old 2day it seems very eerie that once again he has other things goin on,on the side...can someone please help me???