ok guys I need help.....

Please tell me if I am crazy........

Ok well quick backgroung.... my boyfriend and I have been together for a little over a year now and us and my daughter( 3yrs old)living together for about 9 months.

Here it is: I approched him last night because there is a new girl at his work that is pretty, funny, and smart, ( all I thought I was )well she is married but she flirts with him. I am worried that he will cheat on me with her here is why ( and this is what I told him): 1.When we fight he says that ther is nothing between us anymore. 2. his last girlfriend ( of 5years ) that he loved very much( even though she lived far away) he cheated on 3 or 4 times. 3. a girl being married does not bother him , I was when we got together( grantid I was in the last stages of my divorce). His response was that he loves me but I cant help to still think, espically since things are not as "Hot" latley as they have been.
well guys I need to hear the HONEST truth on what you think about this.....