At 18 months, she should already understand the word “no” well. So tell her no when she asks to latch. It’s going to be hard. There will be a lot of screaming and crying. My LOs both rejected the bottle, so my husband spent weeks training them to drink from it. At 18 months, she has other options like straw bottles/sippy cups/normal cups too for milk. Your husband can help you wean her off by doing the milk feeds/patting her to comfort her at night when she’s demanding to latch. My friend also used bittergourd (took some juice to put on the nipple so her LO was turned off). That helped her.
As hard as it is, cold turkey will be the fastest way to wean her off, and you can continue to show her love/comfort her with hugs and kisses. Hope you’ll get through this soon..