Need help..

I and my husband are married for almost 2 years now. We dated for 4 years before marriage... my husband started working at a university in Ethiopia from past one year and I live in a different country.. He used to mention about his female colleague and try n make me jealous about it.. But I've never doubted him and I never felt the need to he was always loyal to me I trusted him a lot. The first time he came back from ethiopia for vacation everything was as usual but now that we were separated for a long time we had more fights than usual. One day I found a chat in his WhatsApp(I jus use it to check all the dps the couples in his contacts put up)to this said colleague without any chats but just the contact in the chat history.. I asked him y he has deleted it and he did not give a definite answer and I din bother much about it. He had bought me gifts from ethiopia and told me that girl helped him shop for me.. I acted angry but I was not n it did not bother me becoz my husband doesn't know shopping for women. After he left to ethiopia we were having even more fights and I was turning into this nagging irritating wife i never wanted to be.. we have fights about me spending on my parents n a hundred other things i nag him to death over it also i had even suggested divorce but he was not ready for it.. anyways he has come back this month on vacation.. the first day he came he used her name while addressing me and I was shocked because this was totally new my husband n i have never had an ex we are both our firsts so this situation had never occurred before. But he justified it was a slip of tongue and I agreed. That night he was sitting next to me n chatting with this girl and wen i turned to him he deleted few of her texts n jept others wen i asjed him about it he denied said that it did not happen at all..later he changed it and told that he deleted it because i might misunderstand and doubt him.. Next day we went out to booze we talked about our misunderstandings decided that we are going to change it etc.. my husband was a lil drunk.. we came home n slept at around midnight he hugged me in his sleep n called her name. I was devastated I din know wat to do. I confronted him and he started telling me that I drove him away from me n towards her etc etc later wen i was crying a lot and told we will have to split he said he was acting that he only said it to test me because I was talking about us splitting.. we had lot of arguments over this since then I'm continuously doubting him.. this is new for me and it's very disturbing. My husband also told me that the only good quality about me now was that I din doubt him and now even that's gone.. yesterday when we were out he got a call from her,in between the conversation he mentioned that I was with him although it was a casual mention it sounded to me like he is alerting her of my presence. Also at night I could see both of them online at the same time on WhatsApp I know it could be coincidence but my suspicious nature is not letting it go.. today morning when I wanted to confirm that he must have texted her I found he has changed his lock pattern in phone and a while later it changed to the old pattern. I'm confused I'm I imagining things or is it because I have doubts on him that i feel everything suspicious or I'm I being played for a fool. I'm worried please advise me. We already have lot of problems between us n i know I'm a bad wife but this will ruin everything I don't wan to be the reason to spoil our marriage. Please help