Cxflygirl -- First of all, good job for BFing so far. Don't feel bad about asking the question. Ideally, everyone should BF 100%, but sometimes we have to find compromises.
When I told my doctor I was sometimes supplementing with formula, he said he still considered that exclusive BFing so long as I wasn't using more than 1 bottle a day. Sometimes women have to start weening, or have to go back to work, or simply have lower milk levels at night.
Anyway... we had the same issue with our daughter, who refused all bottles at first, with breastmilk or formula.
Do have a helper or partner try it. Babies know when mommy's around, and will refuse it because they know BFing is an option.
Sometimes, I'd take a relaxing 15 minute walk outside and let my helper try. Maybe the baby could also feel my own nervousness at her not taking the bottle.
Or try different formula brands. We use Hipp organic, and my mostly BF daughter loves it (now).
And keep with it. 3 tries is not very much. Good luck!