Relationship

I am currently engaged and the thing that's stressing me out is the fact my fiance is in jail and  I currently have zero clue when he comes home, other wise we are making our relationship stronger and twice as better as good as it already was. I love him so much and miss him so so much. 

So my partner wants an open relationship and I don't. I'm trying to make things work but he went and asked out the one person who almost broke us up 4 times. This person used self harm as a way of trying to get attention. My partner said he was fed up with their shit and didn't want to be friends with them anymore. Here recently he hasn't been being open with me at all. I had to get that he is with another person from an outside source. I was pissed that he didn't tell me bcs as one of his partners i have the right to know. I went off on him saying that I was always there for him, i pushed my health-both mental and physical meaning i didn't eat and sleep for like 3 or 4 days- aside so I could be there for him and now hes pulling this stuff. He said he wants us to be open about our feelings but he isn't. I wasn't for a while bcs I didn't know how to put it in words. I had to leave school early today bcs my mental health was so bad that I literally dry heaved infront of my french teacher. I have like 3 ppl I can trust with this information and hes not on SpaceHey at all. I don't know what to do. I've told him how I feel numeros ammounts of times but he won't listen. I love him with all of my being but I feel like it's starting to get one-sided. He says he still cares but won't tell me anything. I had to cry to my friend before advisory for like 20 minutes because I was having a mental breakdown. He saw me crying and did nothing. He just walked right past me and didn't say a word or talk to my friend to see what was going on. I just wish he wasn't scared of commitment. His ex broke him but he can still give it another go. Both him and I know that I'm nothing like his ex but im starting to feel like her. Is there anything possible that I could do?