Your question seemed bit off track to me. You wanted to if analsex causes more wad. But before that the storyline you gave is quite out of the line. WHat you missed out is how old are you, how old he is, did you have sex before and di you have anal sex before.
Honestly speaking, if a guy marries and on the first night the bride wants an analsex, the guy will be a bit surprised. Yes its true not much virgin male and female are available these days when they are getting married, but does the culture accomodative enough when the bride takes the lead and suggest something to make a memorable day? That also some form of sex which is "against the nature".
Anyway, reply to your question, how much wad he will through doesnot depend on anal sex or vaginal sex. Its upto the expectation, the kinkyness, when was the last time he had ejaculation and how long he was having a hardon before the sex. It always ives more cum if the time gap is a bit long and the hardon was for quite some time from the first move.
Yes its a generic trend that when a man gets the momentum and about to go for a climax, its hard to spot when its the point of no return. But there are plenty of others who has a complete control on the orgam, can really delay the climax with their own tricks. I read in a 11th centuray book that suggested how to prolong a sex, even if one gets to point of no return, still can slow down.
I guess I covered your reply, if miss something will reply some other time. But as I said, this loks a story to me where a girl asks for analsex on first night and the man happily comply without any suspicion. Best of luck with your married life and spice up sex on first night, that something new to me. Spice up happens when man and wife fets bored on same routine position and act everynight.