I really really wouldnt be happy. I know that in some circles its seen as harmless 'banter', but I view it differently. And no I've never said anything like that at work. I work with mainly men and theres a lot of swearing, drinking etc and there is some acknowledgement when someone is attractive but that's it, once it's been acknowledged then it's not really mentioned again. Its normally over some customer that's new (when you're having the 'how did the meeting go, what were they like' conversation). There was one guy who used to bang on about what he thought about various women and how hot they were and what he wanted to do to them and he came across as sleazy and sexist.
Other reasons I dont like it -
Does he say nice stuff about you? I'm guessing not because its seen as acceptable to say positive things about other people but not about your partner for some reason and that's quite sad
I feel its disrespectful to you. If my partner said stuff like this, unless he was generous with compliments to me as well, it would be making me paranoid that my ass or whatever wasnt good enough for him and getting naked infront of him would be awkward, I'd be thinking he was thinking about this other woman when we were being intimate etc
It isn't great for his career. If she ever found out (eg saw something left open on his or his colleagues computer or a message flash up on a phone) then he would be in trouble.
Its one thing saying something in that moment eg when someone is bent over infront of you picking something up, it's normal to think 'oh nice ass'. Its not really normal to still be thinking it hours later when you're at home with your partner, and start a message thread to your colleague to have 'banter' about it
Its also just sleazy and disrespectful to her. I mean imagine finding out collesges had been messaging each other about you saying that they wanted to stare at you all day. In most cases, most people would be freaked out, especially if you got on with them and considered them decent colleages or friends
If he is writing stuff like this then I'd be surprised if he isn't actually fairly leery at work. 'I could stare at that ass all day' doesn't really sound likely that in reality he has a quick peek then gets back to his work.
Would he really really be happy with you messaging a colleague when you get back home to say 'god I can't wait for x to present his work to us, I'm going to be staring at his crotch the whole time - you can tell his cock is massive'. Would he just laugh and say 'ha ha that's great bantz'?
I know my outlook is extreme in this and different to a lot of people, me and my husband dont ever sit infront of the tv and say 'oooh hes fit' type of thing (though we would say if asked - I'm not stupid enough to think that people dont notice / appreciate/ fantasise about other people)- I just think doing it publically is a bit disrespectful to your partner especially if it's someone you know in real life and not a distant celebrity