Fb and my boyfriend

So been dating this guy for 5 months now. He's brought up marriage and how he wants to spend his life with me only but he gets random sluty women like half dressed stripper like women leaving comments and likes on his page. It has our pic up as his profile pic and he says just friends? I don't have a issue with him having girls as friends. I have more male friends then girls but they have their clothes on. Should I feel as if he's talking to them behind my back because other wise why would they even respond to anything he has to say? I'm not sure how to handle this but I do know it's causing stress for our relationship! I've have nothing against strippers by the way...been to strip clubs myself just don't like the fact they feel the need to make comments to him and after this long why do they unless he's talking to them also? Need some input!!!! Help...