How would you handle this?

I would just flat out ask him why he did not invite you. Maybe he thought you did not like bowling, but I do find it odd that he would not at least extend the invitation to you knowing you may say no. You mentioned that this has happened in the past and I suspect he thought it was okay not to ask you this time around since you did not say anything last time. Again, please talk to him about this before this becomes a pattern. Let him know that you are interested in attending the events he plans. If when you ask him why he did not invite you and his answer sounds like some BS, he may be hiding your relationship and it may be time to consider whether or not being with him is the best thing for you. Before you come to any extreme conclusions or make any critical decisions, give him the opportunity to explain his behavior to you.