First, make certain that the Q factor is different between the two cranks. Don't assume. Although BF wisdom (such as it is) will almost always claim that triples are wider between the pedals, it's not necessarily so.

Second, if one or the other crank is wider, make certain that the wider Q factor isn't the correct Q factor. It may be some other issue that's causing the problem. For women, it can often be that a little more space between the pedals is a good thing. (And, I wouldn't be shocked to find some compact somewhere that's wider than some triple.)