Do yourself the favor and don't tell your SO. What good would come of it? They won't understand. They will take it personally. They will throw it up in your face from the time you admit it until one of you dies. They will never let it go and use it against you anytime you make a comment that isn't "how wonderful skid is" so don't make yourself miserable. Don't give him ammo against you 

My husband's son is a 34 year old POS.  I do not go into detail about how repulsive and disgusting his son is.  But I did tell him to keep him away from me.  I've never said "I don't like him" - but it's pretty obvious.  All that matters to me is that SS not be allowed in my home or life.

I think the smile and nod approch is best. Say nothing good or bad.

The only time I would differ from that is when the skid is horrible and proves it on a daily basis. Even then, I wouldn't be the one to say you don't like the skid.If and whenDH asks or comes right out and says "You don't like my kid" then yes tell the truth. However, when you do, back it up with all the crap the skid has done or said and ask why anyone, not just you would like such a person.

Is it him you dislike, or his behaviour?

When the subject came up between dh and I, I told him that no, I don't dislike ss5... But I can't handle some of the things he does... And that when he does those things, i prefer to remove myself from the situation than be around those behaviours.

Dh handled a good chunk of those behaviours, and when something positive happens, i lay it on thick.

It also helps than when ss5 is being particularly crappy in the way he's acting and i find dh isn't handling it "enough", I WILL speak up and say things like:

- ss you have a really bad attitude right now...change it or go act that way somewhere else, because I'm not going to be around you if you continue

-i love you but i don't like how you're acting. Go to another room until you can act nicely, then you can come back.

-ss I'm sorry - if you continue acting that way, I won't want to be around you. If you want me to play with you, smarten up.

Every single time I step in to discipline - it's punishment first, then talk. When I punish, i ask if he remembered what I said if he did x or y.. I make sure he spits it out... Throwing a ball in the house - i say throw it again, you go in time out. He throws it.. I ask... What did i say if you threw it again... He pretends not remembering... So i jog his memory.. did I tell you i would take it away, or did i tell you you would go in time out... He'll say time out..  I'll ask if he just threw it again... Yes.. So what does that mean... Time out.. Yes.. Ok go, I'll come get you when it's over...

When it's over... I ask him why he went in time out... For throwing the ball in the house... And why can't you throw in the house... Because it could break something... (Or whatever other reasons I've told him)... I tell him i don't like it when he doesn't listen... He'll say sorry... I say sorry doesn't make everything better, listening makes everything better and that i love him very much but i dont like when he doesn't listen.

For example.

Separating the child from the way the child acts seems to have made dh and ss both understand that the refusal to toletate a certain behavior doesn't affect the love I feel - it just means I want him not to be a shit cuz nobody likes being around a little shit! Lol

My DH doesn't like the very same things about SS that I don't like, but the difference is that he loves his son unconditionally.  He knows I don't love his son. But I don't harp on the negative stuff we both dislike, it doesn't really affect me because he doesn't live here.

yes I have told my fiancé that I dislike his kids. He said he understands and  never gets mad at me. He’s even said it himself that he loves his kids but he made a mistake and should have waited instead of having kids with someone so horrible. When stepkids are here I hideout in my room. I feel so guybut SO doesn’t mind.