Tying the my tubes

my husband has 4 kids I have 1 child and we have 1 child together. I'm getting my tubes tied in 2 days and now out of all timing my husband tells me he wants to have one more baby with me. I have been emotional about this tying the tubes thing for the last week and right as I come to terms with myself, he says that. And it got my emotions all worked up again and now I don't know what to do. I just feel like my body can't take having another baby especially after the 2 losses I experienced in the past before our rainbow baby. I just feel that we have enough on our plates as it is and it is more then enough. Does that sound selfish of me? I am 26 years old and already I'm becoming tired, as in tired like I'm in my 30s or 40s. i just feel this will end my marriage. I need advice and please NO rude comments