Correct, Wolf. The one and only time I've seen two male budgies fight was two brothers, on their first season, vying for the same hen - and this was in a flock of over 30 birds and once in all the years I've kept budgies. Budgies love other budgies. Sometimes, an overly hormonal one would be a bit too insistent on his attentions to his chosen female and she would scold him but that's about it! They never even bicker, they like each other so much!
If Blu is a boy and you get an older hen, it will be perfect. Mind you, by older I don't mean really old, just a hen that is already sexually mature (one year or older) because, if she is too young, he might pester her too much been that he is so hormonal. And, if you get a hand-fed (difficult to find but not impossible) or one that has been living by herself in another home, you should have no problem whatsoever keeping and even improving the relationship you now have with him. If, on the other hand, you can only find 'wild' ones, don't worry too much about it, in my personal experience, budgies that are happy and healthy are easy to tame if you take the time to do it - I don't do anything with mine except clean their flight cage and feed and water but none of them are afraid of me. And I have one that has no feet and a bad wing which spends most of her time on platforms I cover with cardboard and paper (to provide a clean, flat and solid surface for her to stand on) that knows I am going to move her from one to another and just patiently waits for me to pick her up (can't make her step up, she has no feet) and doesn't even blink when I do it -that's how tame they become! And she has an able-bodied boyfriend which hitchhikes a ride on my hand when I move her - that's how tame they become!