Would it bother you if the person you were dating?

Would it bother you if the person you were dating is now best friends with the person they used to be so madly infatuated with? They would always get drunk and have a sleep over. And they became extremely close all of a sudden. And they're always leaving sweet cute comments on each others facebook wall such as "I miss you soo much :(" and "I bet you miss my attractiveness". And your significant other's "best" friend has a picture of the two of them together as their profile pic?