I am a gay male and have been with my partner for 7 years (16 year age gap - 29 & 45). Before I go into the problem that I am seeking advice on, i'll give some background to our relationship. We met online and I had not been with anyone sexually until meeting him. 3 months into the relationship he was still on the dating app that we met on, whereby I confronted him about this and he said he had deleted it following this conversation. Fast forward another 3 months and he was still on the dating app, and I therefore ended things there and then. However, he denied he was on the app and said it was an ex impersonating him (which I don't believe). We got back together approximately a week later. For the next 5 years he has had on and off conversations with guys on social media/text/dating apps of a sexual nature - one of which was his ex, whereby the most crushing thing he said to him was that he loved him more than me. He said he was messing with him and leading him on because he hurt him in the past (which I again don't believe). I ended things (which was about 5 years from the previous break up) however we got back together approximately 2 weeks later. From then I don't believe he has messaged anyone (which has been almost 2 years). Some time in all of this I know he has met someone in person that he has a history with for 'work', however that is as much as I know about it. In all the situations, he somehow initially spins it to something I have done which has led him to do what he has done, for example not making him feel wanted or sexually desirable. I have always stood my ground (i.e stating all the things I do to show I want him), whereby after a few days of failing to convince me I am to blame, he somewhat takes responsibility for his actions.
Fast forward to the present - I have asked him to have an open relationship, whereby on the back of this he is 'very hurt and upset' with me and is blanking me when walking around the house. We've had issues with sex for about 4 years, whereby sex usually leads to something going wrong/me not doing what he wants and it leading to a dispute. I can't say for certain why this is but I am thinking I have some sort of mental block due to everything that has happened. I am happy in every other aspect of our relationship - he treats me well outside of all of this, and has never been physically abusive. He has asked me what I could possibly get from other people regarding sex that I can't get from him, though the bottom line is that we are rarely having sex. We keep having the same conversations that are always initiated by me regarding what we can do to make sex work, however it always ends the same way with it not working. I have remained completely exclusive for the entire 7 years, whereby I haven't even spoke to any other guy in a sexual way, though I am apparently the bad person in all of this for suggesting an open relationship.
The reason I am posting on this forum is because I have no close friends and I have very little family, and I would rather not talk to them about it. The obvious answer is to just leave, however I have severe anxiety that is debilitating both mentally and physically, which I why I have got back together with him on both the occasions we have broke up. My worry is that another 7 years will pass and I will regret staying, however that is not something I can do mentally at this moment. I am also someone that fears feeling regret, and I worry if I leave I would regret it.
Any advice would be appreciated. Thank you.