I Think I have trust issues !

I had two previous boyfriends who both cheated on me badly, now I have a new boyfriend who I've been with for 11 months and just before we started dating he kissed some other girl which I was really hurt by but didn't say anything - he knows now that I was but our friends still make jokes and don't realise it upsets me and he's told them that it does but they continue to do it. I do trust him but about 90% because our friends egg him on to do things. What should I do?