I have no clue on what i need to do?

Me aand my bf have been dating a little over 5 months. I love him! I am 20, i have had relationships and i know this it really love before you make those remarks... anyways, we are really close and very compatable, neither of us like PDA so its cool, i dont care who he talks to or anything until recently... he has been texting this one girl that recently added him to myspace... he doesnt know that I quickly went thru and looked at some of the txt between them because she is supposidly married so i was a little curious... I found a text that he had asked her to send him a pic of her nude/partially nude, and one where he had told her that she is hot... i really love this guy, i mentioned to him that i didnt like that he talked to her that much and he said that is y he doesnt like commitment, i am the only girl he has kept around longer than 2 months. i also saw a txt from her that asked if his gf cared that they talk and he told her naw, which i really dont care who as long as its just a friendship and he isnt telling some chick she is hot! i dont want him to know that i went and looked at it, i trust him and i know that he wouldnt ever actually do something with her, but the fact of some of the text really hurt, i already have a low enough self esteem... i also just dont understand how a girl that recently got married and her myspace seems like she is happy with her husband would want to talk to someone elses bf, i just dont understand. she didnt even say no about the pic... what am i supposed to do? just let it slide bye?