My boyfriend recently posted lyrics on his facebook that make me think he misses his ex, what should i do?

Wait a while: I would wait and watch for any patterns that may bolster that concern. He may need time to work through the lost relationship. That doesn't mean that your relationship with him is flawed or that he misses his ex. Don't be a detective. Let him know you look at his facebook postings and lyrics and if you liked them or not. How he responds may show your concerns about him are unwarranted.

Ask him : The best person to tell you how he feels, is your boyfriend. However, even if he misses her it doesn't necessarily mean he wants to get back together with her. It sounds like you may not be sure he cares for you as much as you do him. Whether this is about your own insecurity, his behavior, or some combination of both only the two of you can say. Therapy could help you with your own part.