Not cumming

Sorry long post...My boyfriend and I have been having sex for about 6 months now and due to our schedules only see eachother about twice a week, but whenever we see eachother we have sex at least 1 time. I'm always wanting more but he seems to have a much lower sex drive than me which we've talked about, but the real problem is for our whole relationship he has only came 3 times in the 6 months we've been sexually active. I've told him about how it makes me self conciousness like I'm not pleasing him and we've had some trust issues with girls on his part so that plays into my feelings there too. He says it's not me and that's all I get from our talks. He brought up getting a cock ring to stay harder longer and we even made plans to get one, ended up having the best sex yet that night and now he doesnt want to get one anymore. This was about 2 weeks ago but now our sex has returned to what it was before. I dont know what to do anymore I feel like hes not putting in the same amount of love as I do for our relationship and it concerns me how he hasn't came in months. Theres been other factors that have played into this but it's too much for one post lol, please give me some advice! ♡