I know - they are such amazing fish - so friendly!
What kind of stand is your 3ft tank on? Reason I ask is that I have a 3ft tank on a wrought iron stand and it was only recently that someone pointed out to me that the bottom of the stand had been designed to take another 3ft tank, which I hadn't noticed before. So I've decided to use that space for three 12" cube tanks (have only got one at present). Is yours on that kind of a stand with space underneath for another tank?
It's a shame that we can only put one male Betta in each tank, isn't it? Imagine how wonderful a tank would look, with half a dozen Bettas in different colours. Wooo!
Don't forget the female Bettas - they can be just as beautiful. I have a gorgeous female - she is a deep purple colour and such a character. I think she actually loves me LOL - if I put my hand in the tank for any reason, she quickly swims over and tries to rub herself against my fingers and her little fins start whizzing round at top speed with excitement. Same if I put my finger on the tank glass - she zooms over and sits next to my finger and if I move my finger along, she swims alongside it. She also loves to be hand-fed directly to her mouth - if I put the food in too far away from her, she refuses to swim to it but sits waiting for me to do it properly!! Yep, she's a bit spoilt!
Unlike male Bettas, you can keep a group of females together (more than 2) and they will usually live happily together once they've sorted out pecking order.
Perhaps that's something you could think about - if you have room for one more smallish tank (don't get anything smaller than a 12x12" for a group of 3 - 4 females though - that's just about the right size to add a filter and heater to and gives the fish enough room to set their territories within the tank)...
Best regards - Athena