If you're talking about couples working together in the same band, well, Paul and Linda McCartney did it for long enough.
As for one or the other being in a band - yes it can. I know loads of couples where this is the case, whether or not the 'non-band' one gets involved with the business or not.
I do think a successful band-couple relationship has to be strong to start with, though. The marriage has to be a very equal one and there has to be a lot of trust and a lot of give and take on both sides. I think the same can be said if you're both playing in the band. You have to have time to be yourself and not just the other one's partner.