IVF with 6 kids already?!

Ok let me give a little backstory on this one...
A dear family friend of mine entered a second marriage some years ago. She came with 3 children of her own and he came with 2, they have since had 1 together. For those not keeping track, that's a total of 6 kids ranging in ages 4-19. She's getting older so back when they had their child together she froze some eggs and he some sperm. Since then they've had their fair share of marital and financial struggles, including her attempting to get implanted and him legally blocking it. The legal block was removed and she was implanted with her last few viable eggs last week. They are still married but they still struggle to keep things together with their family. In my opinion her getting implanted was an incredibly selfish choice. They're constantly struggling to keep their marriage together and have a hard enough time caring for the 6 they have! Her stance has always been that she can't just let the frozen eggs and sperm go because that would be like "throwing her children away". My response has always been, how is it really any different than getting your period every month? I'm sure I'll get some hate lash back for my opinion here but I just don't think it was the best idea for them and their family to do this! What are some other thoughts and opinions on this? Is she behaving selfishly or is she making sacrifices to be a great mother?