You're not being asked to love her less. You're being asked to respect the rights of her father. This is not about you - at all.
Neither of her parents are perfect - nobody is even loosely suggesting that's the case. But again, you've made it about you - seriously, re-read your posts here. There is so much "I" and so little anything else that it's understandable if Dad - however much of a deadbeat loser he may or may not be - is feeling threatened.
It's not about you. It's about this child, and the dynamic between her, her father, and her mother. You are secondary.
Yes, now it's about damage control. If you want that child to grow into a healthy, well-adjusted, secure young lady, step back some. She knows you love her - you know she loves you. There's no need for insecurity on your part, so step back a little.
Do the right thing.