I am not an expert but it seems like you have relationship anxiety /ocd. You have to start trusting yourself and your partner. You have to accept the fact that whatever happens beyond that is not under your control.  I am going to therapy for my ocd/anxiety. My therapist told me that these thoughts/obsessions are not under your control. The way you react is under you control. I understand how it feels these thoughts become so obsessive. Recently i have had thoughts of losing my partner. They were so obsessive that it made so anxious . I said  to myself/ocd let it happen.Whatever may happen i will be fine. People with ocd always look for certainity or want things to be under thier control. So you have start trusting yourself and accept the uncertainity.some things are beyond your control. i know its hard to accept the worst case scenario. But the ocd always latches on what ifs.You might have posted her pic online.How your friends going to react is not under your control. May be try talking to your partner about your insecurities. If you dont work on your obsessive thinking then Ocd might latch on some other decisions that you make.Ocd stems from not feeling good enough.  So thats the reason you will always feel insecure no matter what. start working on yourself. Find a therpist who knows ERP.