I think there needs to be a balance so that you can both compliment and build up your spouse, (despite the unpleasant things on your mind) and also communicate about issues that affect you so that they can be resolved. Bottling up what makes you uncomfotable or worried is only going to bring it to a head at a really bad moment, but that doesn't mean it's wise (or profitable) to offload your feelings the moment they arise. Timing, tone, intent and general approach makes all the difference to what it is you have to say. Perhaps complimenting her dress when the thought enters your head and biting your tongue about your suspicion would be a good start, and then later, after some prayer, you can bring up your concern at a more neutral time in a calm and productive way. At a time when you are both chilled out and spending time together, while neither of you are any longer at the mercy of the vulnerability of the moment, you can say "I want to talk about something that bothered me today so we can clear it up. Remember that dress you were wearing earlier that you looked so good in? It made me a little jealous. I get so worried that other guys are looking at you...." How far you take it at that point might depend on how deep the issue is. You know the dynamics of your marriage better than me So it's up to you to gage whether it's an issue that needs more work or help than a single conversation.
-Love
I agree with this, if it is done in love...a wife should want honor to her husband.
If you were to make the comment positive, but informative.
Like Wow! Heads will be turning tonight! You almost look too good in that dress.
We don't want to make the other ladies husbands covet you.
Maybe you should put a camisole on under that, Or a light sweater on.
Leave it up to her to change the dress.
If a dress just looks bad on me, I would want to know.
My kids have told me the truth, "Mom you look OK in that, but you look better
when you wear this." Sometimes we put on a few pounds and don't realize
that some of our clothes do not compliment us anymore.
My kids joke and say," Mom I think those jeans must have shrunk since the last time
you put them on." And under their breath I hear...muffin top!
It makes me laugh, and go look in the mirror. They are usely right.
I hope this helps, God bless you with loving wisdom!