Be honest!.. that is the only way you can get over all of this.. you are 5 weeks and it is best you tell your current boyfriend you are pregnant and it is not his.. if you both come to an agreement of either an abortion ( which I am against).. or he may just be willing to be in the child's life.. you may never know.. best to be honest and let him know what is going on.. also contact the other male that you engaged with that caused the pregnancy.. if you lie to him and say it is his.. guilt is going to eat you on up.. trust me I know a woman who lied to her boyfriend and cried lots up to 4 months after the baby was born and had to let him know.. you don't want that to happen.. do what is best for that child.. don't lie.. be honest.. best wishes