Sorry for the long post, I’m a rambler when my son is sleeping. 
My sister had the same problem. She has a very Top-10 naming style, so nothing she was suggesting was “out there” in ANY way. He also had the same style, but for some reason was vetoing Everything she suggested and wasn’t being helpful in the least (though he was a bit of an ____, and is now an ex-husband, so he could have just wanted to be difficult). Anyway…she finally got to a point and just told him that she was the one they would had the birth certificate to and she was going to write down whatever she wanted and he could like it or not. After that, he “helped” her decide on [name]Jessica[/name], which was her favorite pick all along.
Our first born’s mn was harder to do than any other name! He decided on it after a [name]LONG[/name] time of me going over countless names and giving him many emailed lists. I think he wasn’t taking the mn with as much consideration/urgency as the fn. We finally got to [name]Alexander[/name] toward the end of the pregnancy by giving him a list of my top 10 middle names and just telling him that he had to pick one from it, since he wasn’t offering up any suggestions of his own and didn’t seem to like any of the ones I was throwing at him individually.
But, in general, I have been Very lucky with my Husband. He actually was the one who picked [name]Conor[/name] as our first’s fn. He was deciding between [name]Conor[/name] and [name]Liam[/name]. I really wanted him to be involved as much as possible and I Really liked both names, so I didn’t bother offering any other suggestions. I felt like it would help create a bond for him from the beginning that I didn’t have to worry about because of my obvious already insanely close bond. The only way I would have been forceful about any name was if he ended up picking [name]Liam[/name], I would have insisted that the middle name in some way was after my father, since He and his dad both have the [name]William[/name]/[name]Liam[/name] connection.
For our twins…before we found out it was twins. I suggested [name]Cormac[/name] for a boy or [name]Cordelia[/name] for a girl. He was 100% on [name]Cordelia[/name] from the beginning. He wasn’t so sure about [name]Cormac[/name], but didn’t veto it. It was too early for him to think/care about it too much. And, by the time I got past the big miscarriage-risk mark and really started about names, he had met a [name]Cormac[/name] [name]IRL[/name]. And slowly after the name had time to settle in his mind, he couldn’t think of a little boy as anything other than [name]Cormac[/name]. After we found out twins, we decided to go ahead and use [name]Cormac[/name] and [name]Cordelia[/name] for both of their names, even though they were more matchy than I would have liked for twins. He also picked their middle names, out of nowhere, as we were getting into bed one night. He just said, “What about [name]Cormac[/name] [name]Sebastian[/name] & [name]Cordelia[/name] [name]Jane[/name]?” I thought they were Perfect, so that was that (other than pointing out he picked [name]Jane[/name] not thinking that it was my mother’s mn, and me wanting to add [name]Marie[/name] to it in some fashion for his mother also…so eventually Janemarie came about).
I think that some men just need the wake-up call of being a little forceful about it and telling them that you need him to participate in a way that you consider to be better/more helpful, or you’re going to pick whatever you want to. And then tell him exactly [name]How[/name] you need him to be more helpful. Hints don’t seem to work, the more straight forward the better.
Let him know that it’s Really important to you, and whether or not he can Understand that, you want him to be Supportive of how you feel and work with you. Point out that it’s a Good thing that you want him to be involved. That you could be one of those women who just pick what they like and are rigid about it, not caring about the father’s opinion.
And with my husband it always helps, for a number of different situations, if I “jokingly” point out how stereo-typically “male” his actions are. He subconsciously starts trying to act in a way to prove me wrong and ends up doing what I wanted him to in the first place! 
I don’t have a significant other, and when I talk about names with my family, if I say, for example, “I like [name]Grace[/name], for Grandma.” Then my mom will gush about how adorable that is I want to honor her mom, my grandma will get this adorable big grin on her face, my sister will complain about how she hates [name]Grace[/name] (she still hasn’t told me why, lol), and my mom will offer up another name she likes (tonight it was [name]Seth[/name], haha). When we talk about names, somehow it just comes out what names we all like. I guess my family has always pretty much liked names, with the exception of my dad. My brother’s not really into it, but he never ceases to make the conversation amusing: