Pulling back when a relationship gets serious, or feeling trapped by obligations that used to feel manageable, can be confusing, especially when you genuinely care about the people involved. Difficulty with commitment often isn't about a lack of interest in others. It's more often connected to fear, previous hurt, or a sense that closeness puts something important at risk. Those feelings don't always come with a clear explanation attached.
Working with a therapist can help you get underneath the pattern rather than trying to simply override it. You might explore what closeness actually means to you, what you're afraid could happen if you let someone in more fully, and whether the way you've been approaching relationships still fits who you are now. This kind of work moves slowly and honestly, but many people find it changes not just their relationships with others but their relationship with themselves in ways they didn't anticipate.