Considering supplementing with formula

My daughter is 7 weeks old. I have been against using formula with my little girl my entire pregnancy, I always wanted to strictly breastfeed. Now after having mastitis twice and an abscess in my breast, I am considering supplementing with formula and only breastfeeding a little. Mostly because I am worried about getting plugged ducts again and having to go through mastitis again. My question is, how can I safely breastfeed less without my ducts getting plugged? I currently breastfeed my daughter every 2-3 hours and I don't want to get engorged and stuff because that would obviously be a step backwards. Of course I'm doing everything I can right now to avoid getting plugged ducts and keep my breasts healthy. I'm pretty sure I'm an overproducer. I'm open to any suggestions.