DID and Marital mayhem (Contains minor sexual commentary)

Ok, so I am DID (or DDNOS, or whatever the DSM-V now calls it).
Co-conscious/co-pilot at almost all times, aware of the others, interact with them + reality fine (mostly).
My girlfriend is aware of this and gets along fairly well with the 3 alters that tend to be present most of the time. Of late, we have been discussing marriage, and that has begun to cause a notable mental block/hiccup. The best way to put it: I tend to leave decisions up to a congress/vote type of thing between myself and the other brainlings. However, I have 2 votes yes (Darius and Jackal), two that won't weigh in, and one of my most primary alters, Hraith, saying no, because he still wants to be with my ex.
Essentially, how does one convince an alter to stop trying to sabotage thoughts and whatnot so I can actually try to do something to make us happy? Is there any way to get an alter to stop pining for the past when everything else and everyone else is willing to move forward?
Of late he's been playing emotional black hole instead of just his professional/stoic self as well, as confirmed during today when he was off in some unknown place and it was just Darius in class, bouncing and not quite wagging his non-tail the entire day...
I'm also curious if it has something to do with sexual behaviors? Hraith was fond of the claim-laying "Mine" statement regarding the ex, and had even slept with her as solo front a few times... but he's slept with the current girlfriend as well... Darius tends to be the social/physical/sexual one, and has had no problem moving on...
Gah.

I like playing with this one! She's fun. And who ended up with that light-up ball? -Jackal's input.

I'm turning to a forum to figure out how to change my own mind...

You have to talk it out with them. Use logic and emotion to appeal to everyone. A pros cons list, conviction, the whole thing most people do when making a decision. Alters are people, you have to treat them the same way because, after all, you are an alter too and it shouldnt be who has the loudest voice, the host, but that everyone has equal input.

Sounds like Hraith needs to grieve and let go. Are any of your alts like a therapist or guide? When there's a major disagreement or something which needs to be worked out, Verumi mediates and gets everyone talking, which is a good start. Once you start understanding their reasoning, you can talk them through things.