Nope, the way FFXIV is made, you can have multiple classes without affecting another. The only class this is not true of is smn/sch since you still only get 30 total skill points and must choose either int for smn, mind for sch, or a mix. So no, your skills and stats will be the same for your whm as any other whm, unless you choose to allocate skill points differently. Leveling multiple classes is actually beneficial due to cross class abilities.