Is this appropriate behavior from a girl that claims to love me? ?

It is unfortunately a fact of life that when a person spends a lot of time with someone of the opposite , things are bound to happen. We girls are especially suckers. If she is confiding in this man and telling him all her problems it is a good bet that he is slowly winning her heart - girls are just emotional creatures. Every heard of this: "no man can serve two masters"? What that basically means is that she cannot invest her emotional self in two men... she will only love one of you. If she isn't spending her time with YOU and telling YOU about her problems, her day, etc. it's a pretty good bet that she is looking elsewhere. There needs to be boundaries if this is going to work out for you two... I'm sure you don't go all touchy feely with girls at the office? It is unacceptable. The sms and her reaction probably just proved her roving eye a bit more. But maybe you still have time to patch up the relationship. Just make sure that you set clear boundaries this time, boundaries you are both willing to keep to!