have a soft spot in (one's) heart for...

 HAVE A SOFT (IN ONE'S HEART) FOR...

Fig. to have a fondness for someone, something, or an animal. 

have an obsession, something that always remains in your thoughts and efforts ...

• I have always had a soft spot in my heart for Lilly, I'll always be her friend.
•  Elaine has a soft spot for kittens.
• I have always had a soft spot in my heart for  India.
• I will always have a soft spot in my heart for 'marron glacé'.
• I love animals and have always had a soft spot in my heart for them.
• "She had a soft spot for her  youngest son, the child won everyone's heart"
• She has always had a soft spot in her heart for self-respect.