anal stuff???

ive always been really uninterested in anal sex since i tried it with my ex and it didnt exactly go well, i dont know if i was too tight or too tense... but it was unpleseant to say the least i lasted like 2 second and a quarter inch.... ANYWAYS everytime my current boyfriend goes down on me and he gets closer to the anal area i get insanely turned on, and he even accidentally fingered my ass once and it was amazing!!! ive already told him about my lack of interest in anal sex so how do i explain to him that i may have changed my mind ?