3 Years of On and Off Toxic Relationship

so I've been seeing this guy on and off for 3 years we both know we're toxic I'm a stage 7 clingy person and he can't express the emotion of love as more then well FWBs and within our 3 years on and off he's cheated on me 3 different times that I know of and continuously talked to other woman on his phone in a sexual and intimate way we've decided to enter a pseudo relationship meaning we're not actually together but we're trying to learn/teach each other how a proper relationship is supposed to be I'm absolutely completely and horrendously in love with him I get upset when he's not with me I text him multiple times a day to see what he's doing and who he's with we live together and share a bed but for the past week I've been dog sitting for a friend and we've been apart I've been getting really anxious that he's doing something he's not supposed to or hanging out with someone I don't approve of or lying to me about something i have access tohis main social media account and I just want to know if anyone has any advice about what I can do to either get over him or since he's actually actively trying to be and do better with me ways I can calm down and stop being so clingy