SO changed mind on family size

My husband and I have been together 7 years, married for 1 year, and have a 2 mo together. We had always agreed on having 3 or 4 kids but after our son was born he decided he only wants one. Our boy is the easiest baby I've ever known- sleeps through the night, natural at nursing, not fussy, overall adorable. Husband is head over heels for him so this decision wasn't made out of stress, and said he changed his mind because he wants to give baby every opportunity in life rather than having to share us/our finances with more kids. He knows how I feel about it and would not say something like that lightly. He's also a very by-the-book guy who doesn't like changing course from his plan so for him to change his mind on something this big is extremely uncharacteristic.Even though it's only been 2 months since our child was born I feel like this is a very permanent decision for him and something he put a lot of thought into before telling me. My siblings are a huge part of my life and now that I have a family of my own it's important to me that my kids experience those kinds of relationships as well. I just don't feel like our family is complete but apparently my husband does... How do we get past this? This was such an important topic to both of us that we discussed at length before getting married and as much as I want to respect my husband and his feelings (things can change, I get it), the childish part of me wants to throw a fit at how unfair this is for him to do. It almost feels like a death sentence for our marriage. via /r/Parenting http://bit.ly/2BG2lZR