O dear what a difficult situation for you, I can really get your pain and confusion. Bete aap toh apni taraf se koshish karhi rahe hain na, aur yeh baat aap khud ko aur apni partner ko samjhiye ki Shyadi kisi viykati ki past life mein kuch acha ya bura ghat jata hai, toh agye badhne ke liye purani baton ko bhulna hi padta hai, apki partner ko bhi yeh samjhne ki zarurat hai . Ismein us teesre insaan ka kya roll hai ? yeh present aur future aap dono ka hai aur bete aap dono hi milkar isse achha aur swasth bana sakte haain. Aap ne jitni koshish ki who achhi hai ab apki partner ko bhi apka saath dena zaruri hai. Explian to her you need her full attention and support at this time. Its brave of her she told you, we must appreciate that as well, but the important thing is that was in her past. Now if you really want to make a futire with her, try and let this pass over. Also one short term strategy could be you avoid meeting that guy for a while and cement your relationship with her. Jab aap dono ka rishat aaur bhi mazboot aur swasth ho jaayega, shayd aap is vyakti ko better she sakenege. See what works – all the best.