I know there are many opinions on this subject, but I am in stark contrast to the first poster. I have always thought of self stimulation as a completely normal and expected part of life, even in a marriage. I actually have a hard time fathoming that there are people or couples out there that don't EVER do it... THAT actually seems far more odd to me than people occasionally self pleasuring. I don't feel betrayed WHATSOEVER when my fiance helps himself. Now, of course, if he were regularly doing that in place of desiring intimacy with me, naturally that would be a problem. But I have no issue at all with him occasionally releasing some tension, say, in the shower.
My libido isn't quite what it was in my 20's, but I do still somewhat regularly feel in the mood. And even if I'm not particularly in the mood, if it's been a little while since the last time, I will go along with things, and inevitably do get enjoyment out of it, once we start. But my sex drive pales in comparison to my fiance's, so I am actually glad that he doesn't mind taking care of himself once in a while, rather than expecting me to be at his beckon call each and every time he's feeling like he needs a release.
We have lots intimacy, and we do a lot for each other. We take the time to meet each other's physical and emotional intimacy needs. I don't feel that there is anything lacking, or that he feels I'm not meeting his needs, and conversely, that he's not meeting mine. wink wink. So the once in a while self-service is not a big deal, at all. I just don't feel threatened by my fiance's hand.
So as you can see, I am in the court of *don't sweat it* unless you see it as a factor of something bigger, like you aren't having enough intimacy between you, or you are feeling otherwise not connected, which you kind of suggested. If that's the case, then I'd work on getting the fire re-ignited between you and work on rekindling your intimacy. However, if all else is well, in the bedroom and otherwise, a little self pleasure here and there is no big deal at all, totally normal, and totally acceptable, IMHO.