I'd keep the laptop too.
Your bf probably has all kinds of great ideas and intentions while in the safe environment of rehab. The real test is what he will do when he gets out and has to deal with life on life's terms. Only then will you know where he is headed.
You say you love him. But do you really want to spend the rest of your life living with the possiblity of relapse and everything that goes along with it? Take this time to focus on YOU and what YOU want and don't feel bad about it... You have alot of healing to do too.