Here is a dua to increase love between husband and wife. This will also help to heal any relationship problems. It is recited by Saad Al Qureshi.

إِنَّ الَّذِينَ آمَنُوا وَعَمِلُوا الصَّالِحَاتِ سَيَجْعَلُ لَهُمُ الرَّحْمَٰنُ وُدًّا اور جو لوگ ایمان لائے اور عمل نیک کئے خدا ان (کے دل) میں محبت پیدا کردے گا

Verily those who believe and do good deeds, ARRAHMAN will appoint for them love. Surah Maryam [19:96]