Hello sezmac & welcome.
This girl has a reputation for inappropriate behaviour and your partner has a reputation for not cheating, so that is a good sign, as far as your relationship is concerned
The thing that I find a bit strange is that this girl was with your partner about 2-3 years ago, and you have been with your partner for nearly a year, so, if she was and remains so excessively attached to him, why has it taken until now for her to bombard you with (false) allegations?
You have posted here because of your concerns ~ but are your concerns about how to deal with this harassment, or about whether to believe your boyfriend?
Your thread title indicates that you are 'Not sure what to believe', so the seeds of doubt have certainly been sown.
Is this all she wanted to do?
Or is there some truth in her allegations?
Much is going to depend upon your relationship with your boyfriend and how much you trust each other.
Her saying that she is Christian seems irrelevant. She may or may not be a Christian, but, either way, some Christians lie and some have extra-marital sex, anyway.
What does she want?
Does she want him back, or does she just want to end your romance?
How can you be sure that your partner has never knowingly lied to you?
If you were to discover that she were telling the truth, how would this affect you and your relationship?
How well do you really know him?
I believe that, in some relationships, it really is possible to know that you can trust your partner and believe what he says ~ but not all relationships are like this and not everyone is right about who to trust.
I am certainly not suggesting that your boyfriend is lying, but someone is, and you need to be comfortable, in your own mind, with which truth you accept.
Why might this girl have started doing this now?
Has she ever tried to ruin your relationship before?
Does he keep in touch with her?
Could she have seen him and re-ignited her feelings for him in some kind of imaginary scenario?
What about her friends ~ are they just trouble-makers or do they believe her story?
Do you know any of them, yourself?
Can you just ignore all of the fuss and ride it out?
