It's challenging to determine the specific reason for your boyfriend's change in behavior without more information about his situation and the dynamics of your relationship. However, I can offer some possible explanations for his behavior:
Emotional Distress: Rehab can be a stressful and emotionally challenging time for individuals trying to overcome addiction. Your boyfriend's focus might be on his recovery, and he may be experiencing a range of emotions that affect his ability to express love or other feelings verbally.
New Rules or Guidelines: Some rehab facilities have specific rules or guidelines regarding communication with loved ones. It's possible that your boyfriend is adhering to the facility's rules or recommendations, which may affect how he communicates during phone calls.
Focusing on Sobriety: In early stages of recovery, individuals often prioritize their focus on achieving and maintaining sobriety. This intense focus might lead to changes in communication patterns as he works on his recovery.
Feeling Overwhelmed: Rehabilitation can be an intense and transformative experience. Your boyfriend might be feeling overwhelmed, which could impact his ability to express emotions during phone calls.
Fear of Relapse: Your boyfriend may be cautious about expressing love or making emotional commitments while in rehab, fearing that it might distract him from his recovery or trigger feelings that may be associated with substance use.
Changes in Relationship Dynamics: Entering rehab can lead to shifts in relationship dynamics. He might be trying to navigate the changes in your relationship and determine how to best support his recovery and your connection simultaneously.
Communication Skills: Some individuals find it challenging to express emotions or say "I love you" under regular circumstances, let alone during a challenging time like rehab.
It's essential to approach this situation with empathy and understanding. Recovery is a highly personal journey, and everyone's experience will differ. If you have concerns about your relationship or his progress in rehab, consider having an open and honest conversation with him when the time is appropriate. Remember that his focus should be on his recovery during this time, and support from loved ones can play a crucial role in the process. If you feel uncertain or overwhelmed, you might also consider seeking guidance from a counselor or therapist who can help you navigate this challenging time.