Hello Sin tu Amor, He must have a reason of course to do so. He might want to be assured that she loves him by testing her reaction. She maybe giving him little attention and care and he is craving some by arousing her jealousy. He maybe only sick and wanting to annoy her (where in this case she better reconsiders the whole relationship). Those feelings of jealousy could be reasonable and justified ,but in other cases also a sign of insecurity and lack of self confidence. If a woman feels good about those feelings then they are acceptable, if they make her feel less at ease in the relation ,then she should be aware of his real intention and question the whole thing.