am I being selfish?

so my husband wants to go into the service. he wants to work towards being in special forces. We have 2 kids and are trying for #3 right now he's a diesel mechanic and makes decent money. We have a lot of debt and 2 trucks were currently paying off. right now were doing well but we need the income around at least 3,000 a month to make it. And he's making around 4,000 a month. he wants to go right away. he has heart problems but wants to try to keep that a secret to go in. honestly it's been his dream since he was little and he even went into the little marines. I think it's a selfish decision to leave all of us to go through basic etc. I would have to work 2 jobs to make it and idk what I would do with our kids.( I'm currently a sahm) and he doesn't care that he would be away from his son's for long periods of time.... this has been an issue for the past 2 years.... am I being horribly selfish, or is he? I think he should've done that before we made a family. he thinks I'm a bitch for not being all for it... also our kids are2 and 9 months