Aaron Carter's Ex-Fiancée Hurt by Mom's Accusation, on Good Terms Before Death

Aaron Carter's mother accused his fiancée of causing his death, but Melanie Martin says not only is that not true … it’s also downright hurtful based on the reality.

Melanie tells TMZ … posts publicly shared by Aaron's mom, Jane Schneck, last week -- in which she outright accused MM of killing her son -- are completely contradictory to what she says was a fairly good relationship with Jane before Aaron passed.

While he was alive, Melanie says Jane would often thank her for having Aaron’s best interest at heart -- and that she explicitly expressed to her that she knew how much Melanie loved Aaron.

One example … Melanie says while she was helping Aaron get his teeth fixed -- Jane was singing her praises and called her a good woman. It's because they used to have that kind of relationship that Melanie says Jane's attacks are so hurtful.

Despite that, Melanie tells us she doesn't hold the posts, which have since been deleted, against Jane -- she knows everyone in Aaron's life is grieving in their own way.

There's also this … Melanie says after Jane's posts, an assistant for Aaron’s sister, Angel, called her directly to apologize, and to let her know they were taken down.

Melanie also says she's been invited to the memorial the family will hold next year to spread Aaron's ashes.

For what it's worth, Melanie points out she was one of the few people still actively trying to help Aaron when he died -- and says she too is still mourning the loss.

Melanie wants to make peace with Jane, because she tells us it's still her hope for Prince, her son with Aaron, to meet his grandma after Christmas -- as they'd planned to do before Aaron was found dead at his home last month.