I say don't make your DH attend unless it is a co-ed shower - and if it is, pleeeeeeease do it like a grown-up party, not a lady's lunch! To me, there's almost nothing worse than showing up to a co-ed shower (having begged DH to go, promising there will be other men there), only to find it's all girly decorations and cheesy games in which the men are expected to participate. Don't be that MTB! Your friends' husbands will never forget...
That said, we had a very successful co-ed shower for my brother's wife. We barely knew her (they met in the military, and she'd only been to visit our hometown a couple of times for short trips), so we thought she'd be more comfortable with him instead of in a room full of strange women. We had the party in the late afternoon / early evening, invited all kinds of couples and families, and served a light buffet plus beer and wine. Basically, it was just a regular summer party, with thirty minutes of gift opening towards the end.
ETA: The gift-giving at the end was announced very casually - my sister and I announced in each room and on the deck that the mother-to-be will be opening presents in the parlor in a few minutes for those who would like to watch. Really only the women (and my brother) sat for it - the men smiled and nodded at the invitation to watch, then milled around in another room, drinks in hand. It really worked well...