With my lover, last 1 month I have more misunderstanding with her, i was so upset ,I love her sincerely more?

With my lover, last 1 month I have more misunderstanding with her, i was so upset ,We both loving sincerely for more than 3yrs, but one day she said that i was in in love with a guy before at the age of 14 he called me he said still he is loving me but she not accepted that, but when she talks with me she speak with a optional I dont like this create us big fight even 2 times I tried to attend suicide for that she is y life. But now she promised that she will marry only me but also she is not like before she changed lot not behaving with me like before Iam expecting the more love and care from her wat i do?