Why do I feel indulgent?

While it's completely natural to want to experience a pregnancy and parent a baby I have such a sense of guilt about it. Donor egg IVF comes with a whopping price tag! I was explaining to Ivan last night that I just can't ignore this intense desire to attempt another IVF. It's like a deep calling that I can't ignore and feel like I shouldn't ignore. But, why does it make me feel indulgent and selfish? I think there has to be more to it than that and I was trying to explain it last night. For starters, my girls are old enough to benefit from sharing in a pregnancy experience with us...they would sincerely enjoy following all of the stages, going to doctor visits, etc. My youngest is desperate to be a big sister...she would positively blossom in that role. And what about this life we would be creating that would never exist otherwise? I know he or she would bless this earth with his/her talents. It has has been gnawing at me, this desire to try IVF again. Maybe I am just trying to make myself feel better by suggesting there are higher power hands in the matter. What ever the source of the tunnel-vision-drive to see this through, I am overcome with humble joy that it is happening again.