3. He Holds on to Sentimental Gifts from Her

So, he has yet to throw away that T-shirt she bought for him at that one music concert. Then, when you ask to wear it to bed, he gets super protective and makes you take it off because it was a gift from his ex.

Well, he may just be holding on to it as a reminder that she still means a lot to him. Anything that triggers an emotional response should be perceived as a major warning sign. It's completely understandable that certain gifts shouldn't be tossed away and forgotten, such as his vehicle she helped him purchased prior to the relationship. However, if there are unnecessary gifts located around the house or in a trunk for keepsake, then there's honestly a problem there.