I had an Aries bf that acted fairly similar... like he never cheated (but he would do stuff with many other girls whenever we took breaks from each other), but he told me that he thinks about having sex with other girls, watches porn regularly, and he too also made me guess his sexual orientation by the way he was with other guys. In the end, it was too much for me to handle. I tried to deal with it and help him through whatever issues he was going through, but being a Scorpio... I just couldn't handle my own jealousy and feeling as if I was somehow inadequate. I was never the problem and neither are you.