I will probably get some hate for this, but if done properly I see no problem with what you propose. What worries me is that you call this a fetish, and say, "I really am turned on by the thought of someone cumming in me and possibly getting me pregnant." If you're thinking of making a baby, a new human, it had be better thought out rather than just something that turns you on.
First and foremost, is your husband ok with you getting pregnant by another man and is he willing and capable, financially and otherwise, of caring for the child? (Have you both been tested to see if he has swimmers and your eggs are good?) If so, then it is no different than sperm donation or adoption. If not, don't do it.
As to the other guys, once they pump their cum into you it's a gift and all your choice on what you can do: abort, have the child and keep bio dad out of it, or pursue bio dad for support. There are numerous discussions about whether that is all fair, but that's the way it is. Although I think all states automatically make any child born in a marriage the husband's child, you may also want to consult a family lawyer. (Consider again how this isn't fair - if a married man gets a single girl pregnant, the law doesn't just let the couple claim the child as theirs.)