Im still not happy about the dead wife.

Ok. So I've been with my boyfriend now fiancé for almost 6 yrs. When i met him he was a widower with a 3yr old girl. Now 6yrs and two boys later. Im feeling resentful again. Like when i had my first born i felt like he wasn't as excited as i was he already had a kid this was my first one. And now again with the whole wedding situation. He's been married before this is my first time. How do i get rid of the feeling that im in competition with someone who is dead.