I would have to ask what your age is, and his....because there's a difference in "being checked out by a man" in the sense that anything beautiful is going to get a glance or some attention, that's normal. I mean I am sure, no positive, that my husband loves it when I look my best and we are together and others might look. I am really proud when he's on my arm and another woman might look his way...but I'd have a problem if she walked up and propositioned him, but so would he. That would be a lack of respect for my marriage and me. Women are like a crown jewel on a man's arm and when other men notice his woman is nice looking, I think it does make a man proud.
It's not what "other women" do, crushes, flirting, what have you....it's the reaction or ACTION that your man takes on it. For instance if a woman comes on to him, and he responds with the intention of letting her know he's interested....that's a big sign...like one that he's likely to "act" on the invitation. But if he responds like he should, he should be able to let her know that under no circumstances is he available or willing to take her up on any kind of "activities" that would jeopardize his character or relationships. It's really about trusting him, not worrying about what other woman do, but what he does.
I know my husband is good looking, heck, that's one reason I was attracted to him. If you think you are the only human alive that will find your man attractive...you are wrong. Just as I am sure other men might find me attractive and my husband knows that. Not being vain, but we all have a differing degree of what we find attractive in others and what we don't. I am positive that other men like certain "things" on a woman, therefore, they are going to notice those "things". Whether that be long hair, long legs or nice toes....someone is going to notice our mates, or their women. It's dwelling on a certain person in more than a "nice" way....like actually pursuing that person with the intention of making it more than just "admiration" from a far. That's when there's a problem. And I am sure you know of the "look" that we ALL are capable of putting out there to draw "sexual attention" to ourselves, and that sometimes needs a little adjustment for some....who need that kind of attention because they lack it at home, so they put themselves in situations where they "look needy of attention" from the opposite sex. And believe it or not, men are real preceptive of woman who do this....and it's not always "attractive" to them either. It's one of the first things I think of when I meet a man who goes beyond "looking" and takes things to another level with a married woman....there's something lacking in that kind of person, and I know it right off the bat.
I think we all get, well, maybe not "all"...but we should strive to have a special place in our partners hearts, their thoughts, and what WE have that only WE have that makes us special to them. In other words, there are things about US that only they know. We don't share those things with anyone else but them. Ex: My husband has some "favorites" that no one but myself knows about. And it should be that way. He also knows my "favorite" things that he does, that I don't share. These are things that I am "confident" about our rlsp. And no amount of "looks" that anyone else has is going to change that about us.
Since you know about this "26 yr old girl" at the office, then it's safe to say, he's told you some things about it. Hence, he's devuldged this info and is not hiding it. That's a positive thing. If you must talk about it...ask him how he responds to her. I am sure he's not provoking her or leading her on. If you have to...ask him about it. But know this....when you drill a man about such things, you are really suggesting that his "character" is in question and that you need some reassurance from him that he's "happy" with you....so be direct about asking him that. Don't "beat around the bush" and get ticked at "her" when the power lies with him as to how he behaves.
There are 26 year old blondes walking all over the world....and if that were the "threat" that you really have to concern yourself with....then you will never be secure in who you are with him. And that's really where you should spend that energy getting to WITH HIM. If a man is smiling when he leaves the house....and smiling while leaving work to hurry home to you....other woman usually get the "hint" that he's pretty much taken care of......get my drift here?
Luv~