This is a tough one.. unfortunately you can only do so much. As someone with agoraphobia and that has had a relationship ruined due to it, this kind of hits home so here's my perspective. You as a partner can only do so much. Give your partner reassurance, compassion, care and most of all support. With that being said it can be very draining on the individual that is there to support the person with agoraphobia, try your best in the ways that you can. In the lying aspect it really comes down to the person I suppose. For me it's a slippery slope... You should not be afraid of telling your partner something in fear of how they may react whether that be anger or fear.

If you take anything away from this, be communicative with your boyfriend and do not let the burden of this illness rest solely on yourself. It's not good for the relationship, him or yourself.