Should i have an abortion?

Me & my husband went through a rough time recently and i was sure that we are going to divorce. then i met someone else and we got quite serious very quickly. eventually me and my husband worked things out. i stopped seeing the other guy and now i got news that im pregnant. i know that it is the other mans child and i really want to work on my marriage so don't no what to do. my husband knows about the other man, but still thinks its his child and i don't have the heart to tell him otherwise. i really don't want to build our future on betrayal and lies and prefer to have an abortion and then get pregnant immediately again to give my husband a baby. it will be our first child together so i wanna do this right.