Hi
I'm so sorry you lost your girl. (((HUG)))
I am going through the same thing. I had to have my old boy pts 3 weeks ago tomorrow, heartbreaking.
We started off with 2 dogs, girl and a boy, like you. Ours were 2 years apart. When we lost our old girl, 2 years ago, our boy really seemed to feel it. He looked so sad, and it was if a bit of 'life' had gone out of him. I suppose it's completely understandable, they had been together for over a decade !
Our instinct was to get another dog, but not immediately, and not just because we felt he needed a friend. We did feel he needed a friend, but we were also very cautious as he was getting older himself, so did not want to upset him in his later years.
It's hard to explain, you can only do what's right for you, and your dog. We got a puppy, who is a completely different breed about 14 months after our girl died. We had a lovely breeder who completely understood our situation, and was more than prepared to have pup back if she didn't get on with our boy.
She settled in really well, and our boy was very accepting of her, and was actually very helpful in teaching her how to behave ! They certainly didn't have the relationship that the original dogs had, but I never expected them to, they did get on really well, it wasn't just a tolerance thing, I think she perked him up a bit, and he realised life can be fun...
As I said, we lost him 3 weeks ago, quite suddenly but half expected, if you know what I mean...puppy is now over a year old. I think she misses him, but not as much as he did when we lost our original girl...I'm sorry if I'm not making much sense ?
Because we have only had her a relatively short time compared to the other 2 dogs, and because her time with him was shorter, I don't think she feels his absence so much, as she has us all to herself now...so the gap that may have been left has been filled, but by us.
We're not getting another dog, not just in relation to her but expenses etc as well, I really wouldn't want to encourage you one way or another, just say that it has to be your decision, as long as you are aware of all the pitfalls that can happen, then only you can decide what's best/right.
Your boy might not want to accept another dog, and may grow to love being the only dog ?
It's such a hard decision, because some people will say yes, with good reasons and some will say no, with good reasons. Only you and your family can decide, and perhaps try and see what happens ? You know your boy best, his temperament etc...would he tolerate a new face ?
I would also say, allow yourselves time to grieve, fluffy boy included. It may be that you are thinking about it too quickly, and bad decisions can be made, which then become a nightmare !
It may be that over time he will give you the answer you are looking for ? He may be perfectly thrilled to be the only dog, and have you and the family devoting yourselves to him ?!
I'm not sure I'm best placed to advise about breeds/sex etc, I can only offer an opinion, but if you want to chat further I'm here.